mirror of
https://github.com/donnemartin/interactive-coding-challenges.git
synced 2024-03-22 13:11:13 +08:00
Add search sorted matrix challenge
This commit is contained in:
Donne Martin
parent
3e67ffea39
commit
1208e1110f
0
sorting_searching/search_sorted_matrix/__init__.py
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0
sorting_searching/search_sorted_matrix/__init__.py
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Challenge Notebook"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Problem: Search a sorted matrix for an item.\n",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)\n",
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"* [Solution Notebook](#Solution-Notebook)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Constraints\n",
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"\n",
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"* Are items in each row sorted?\n",
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" * Yes\n",
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"* Are items in each column sorted?\n",
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" * Yes\n",
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"* Is the sorting in ascending or descending order?\n",
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" * Ascending\n",
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"* Is the matrix a rectangle? Not jagged?\n",
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" * Yes\n",
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"* Is the matrix square?\n",
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" * Not necessarily\n",
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"* Is the output a tuple (row, col)?\n",
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" * Yes\n",
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"* Is the item you are searching for always in the matrix?\n",
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" * No\n",
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"* Can we assume the inputs are valid?\n",
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" * No\n",
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"* Can we assume this fits memory?\n",
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" * Yes"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Test Cases\n",
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"\n",
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"* None -> Exception\n",
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"* General case\n",
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" * Item found -> (row, col)\n",
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" * Item not found -> None"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Algorithm\n",
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"\n",
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"Refer to the [Solution Notebook](). If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Code"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class SortedMatrix(object):\n",
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"\n",
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" def find_val(self, matrix, val):\n",
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" # TODO: Implement me\n",
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" pass"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Unit Test"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"**The following unit test is expected to fail until you solve the challenge.**"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"# %load test_search_sorted_matrix.py\n",
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"from nose.tools import assert_equal, assert_raises\n",
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"\n",
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"\n",
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"class TestSortedMatrix(object):\n",
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"\n",
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" def test_find_val(self):\n",
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" matrix = [[20, 40, 63, 80],\n",
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" [30, 50, 80, 90],\n",
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" [40, 60, 110, 110],\n",
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" [50, 65, 105, 150]]\n",
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" sorted_matrix = SortedMatrix()\n",
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" assert_raises(TypeError, sorted_matrix.find_val, None, None)\n",
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" assert_equal(sorted_matrix.find_val(matrix, 1000), None)\n",
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" assert_equal(sorted_matrix.find_val(matrix, 60), (2, 1))\n",
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" print('Success: test_find_val')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestSortedMatrix()\n",
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" test.test_find_val()\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Solution Notebook\n",
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"\n",
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"Review the [Solution Notebook]() for a discussion on algorithms and code solutions."
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.5.0"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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@ -0,0 +1,223 @@
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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Solution Notebook"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Problem: Search a sorted matrix for an item.\n",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Constraints\n",
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"\n",
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"* Are items in each row sorted?\n",
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" * Yes\n",
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"* Are items in each column sorted?\n",
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" * Yes\n",
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"* Is the sorting in ascending or descending order?\n",
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" * Ascending\n",
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"* Is the matrix a rectangle? Not jagged?\n",
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" * Yes\n",
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"* Is the matrix square?\n",
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" * Not necessarily\n",
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"* Is the output a tuple (row, col)?\n",
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" * Yes\n",
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"* Is the item you are searching for always in the matrix?\n",
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" * No\n",
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"* Can we assume the inputs are valid?\n",
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" * No\n",
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"* Can we assume this fits memory?\n",
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" * Yes"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Test Cases\n",
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"\n",
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"* None -> Exception\n",
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"* General case\n",
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" * Item found -> (row, col)\n",
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" * Item not found -> None"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Algorithm\n",
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"\n",
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"<pre>\n",
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"\n",
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"Find 60 (val = 60)\n",
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"\n",
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" 20 40 63 80\n",
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" 30 50 80 90\n",
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" 40 60 100 110\n",
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" 50 65 105 150\n",
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"\n",
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"* If the start of a col > val, look left\n",
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"* If the end of a col < val, look right\n",
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"* If the start of row > val, look up\n",
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"* If the end of a row < val, look down\n",
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"\n",
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"If we start at the upper right corner, we just need to use these cases:\n",
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"\n",
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"* If the start of a col > val, look left\n",
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"* If the end of a row < val, look down\n",
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"\n",
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"</pre>\n",
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"\n",
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"Complexity:\n",
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"* Time: O(n + m), where n and m are the matrix dimensions\n",
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"* Space: O(1)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Code"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class SortedMatrix(object):\n",
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"\n",
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" def find_val(self, matrix, val):\n",
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" if matrix is None or val is None:\n",
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" raise TypeError('matrix and val cannot be None')\n",
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" row = 0\n",
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" col = len(matrix[0]) - 1\n",
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" while row < len(matrix) and col >= 0:\n",
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" if matrix[row][col] == val:\n",
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" return (row, col)\n",
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" elif matrix[row][col] > val:\n",
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" col -= 1\n",
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" else:\n",
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" row += 1\n",
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" return None"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Unit Test"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 2,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Writing test_search_sorted_matrix.py\n"
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]
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}
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],
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"source": [
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"%%writefile test_search_sorted_matrix.py\n",
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"from nose.tools import assert_equal, assert_raises\n",
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"\n",
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"\n",
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"class TestSortedMatrix(object):\n",
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"\n",
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" def test_find_val(self):\n",
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" matrix = [[20, 40, 63, 80],\n",
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" [30, 50, 80, 90],\n",
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" [40, 60, 110, 110],\n",
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" [50, 65, 105, 150]]\n",
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" sorted_matrix = SortedMatrix()\n",
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" assert_raises(TypeError, sorted_matrix.find_val, None, None)\n",
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" assert_equal(sorted_matrix.find_val(matrix, 1000), None)\n",
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" assert_equal(sorted_matrix.find_val(matrix, 60), (2, 1))\n",
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" print('Success: test_find_val')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestSortedMatrix()\n",
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" test.test_find_val()\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 3,
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"metadata": {
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"collapsed": false
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},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"Success: test_find_val\n"
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]
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}
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],
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"source": [
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"%run -i test_search_sorted_matrix.py"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.5.0"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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@ -0,0 +1,24 @@
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from nose.tools import assert_equal, assert_raises
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class TestSortedMatrix(object):
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def test_find_val(self):
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matrix = [[20, 40, 63, 80],
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[30, 50, 80, 90],
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[40, 60, 110, 110],
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[50, 65, 105, 150]]
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sorted_matrix = SortedMatrix()
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assert_raises(TypeError, sorted_matrix.find_val, None, None)
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assert_equal(sorted_matrix.find_val(matrix, 1000), None)
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assert_equal(sorted_matrix.find_val(matrix, 60), (2, 1))
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print('Success: test_find_val')
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def main():
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test = TestSortedMatrix()
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test.test_find_val()
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if __name__ == '__main__':
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main()
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