Update compress challenge

Fix some bugs

arrays_strings/compress/compress_solution.ipynb

@@ -2,30 +2,21 @@
  "cells": [
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
    ]
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "# Solution Notebook"
    ]
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3BC2D4'.  Only compress the string if it saves space.\n",
     "\n",
@@ -33,15 +24,14 @@
     "* [Test Cases](#Test-Cases)\n",
     "* [Algorithm](#Algorithm)\n",
     "* [Code](#Code)\n",
-    "* [Unit Test](#Unit-Test)"
+    "* [Unit Test](#Unit-Test)\n",
+    "* [Bonus C Algorithm](#C-Algorithm)\n",
+    "* [Bonus C Code](#C-Code)"
    ]
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "## Constraints\n",
     "\n",
@@ -58,10 +48,7 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "## Test Cases\n",
     "\n",
@@ -73,10 +60,7 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "## Algorithm\n",
     "\n",
@@ -102,10 +86,7 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "## Code"
    ]
@@ -114,9 +95,7 @@
    "cell_type": "code",
    "execution_count": 1,
    "metadata": {
-    "collapsed": false,
-    "deletable": true,
-    "editable": true
+    "collapsed": false
    },
    "outputs": [],
    "source": [
@@ -144,10 +123,7 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "deletable": true,
-    "editable": true
-   },
+   "metadata": {},
    "source": [
     "## Unit Test"
    ]
@@ -156,9 +132,7 @@
    "cell_type": "code",
    "execution_count": 2,
    "metadata": {
-    "collapsed": false,
-    "deletable": true,
-    "editable": true
+    "collapsed": false
    },
    "outputs": [
     {
@@ -216,9 +190,104 @@
    "source": [
     "%run -i test_compress.py"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## C Algorithm"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This algorithm is based on Python Algorithm\n",
+    "\n",
+    "Define a 'result' (the compressed string) with the string's len .\n",
+    "\n",
+    "* First, for each element into the string\n",
+    "    * If the element (char) is as the last char, we increment the count\n",
+    "    * Else\n",
+    "        * Concat the last char and count into the 'result'.\n",
+    "        * make the last char = char\n",
+    "        * count = 1\n",
+    "           \n",
+    "* Then, concat the last char and count into the 'result' \n",
+    "\n",
+    "* Finally, if the 'result' (compressed string) size is < string size\n",
+    "    * Return 'result' string\n",
+    "* Else\n",
+    "    * Return string"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "# %load compress.c\n",
+    "#include <stdio.h>\n",
+    "#include <stdlib.h>\n",
+    "#include <string.h>\n",
+    "\n",
+    "\n",
+    "char *compress (char *s);\n",
+    "char *_calc_partial_result (char p_char, char count);\n",
+    "\n",
+    "int main ( ){\n",
+    "  printf(\"%s\\n\",compress(\"AABBCC\"));\n",
+    "  return 0;\n",
+    "}\n",
+    "\n",
+    "char *compress ( char *s){\n",
+    "  char *result = (char*) malloc(strlen(s)); // result string\n",
+    "  char prev_char; // previous char\n",
+    "  int count = 0; // count defines\n",
+    "  char *p_count;\n",
+    "  int i;\n",
+    "  if(sizeof(s) == 0)\n",
+    "    return NULL;\n",
+    "  prev_char = s[0];\n",
+    "  for (i=0; i<strlen(s); i+=1){\n",
+    "    if (s[i] == prev_char)\n",
+    "      count+=1;\n",
+    "    else{\n",
+    "      asprintf(&p_count, \"%i\", count);\n",
+    "      strcat(result, _calc_partial_result(prev_char, *p_count));\n",
+    "      prev_char = s[i];\n",
+    "      count = 1;\n",
+    "    }\n",
+    "  }\n",
+    "  asprintf(&p_count, \"%i\", count);\n",
+    "  strcat(result, _calc_partial_result(prev_char, *p_count));\n",
+    "  if(strlen(result)<strlen(s))\n",
+    "    return result;\n",
+    "  else\n",
+    "    return s;\n",
+    "}\n",
+    "\n",
+    "char *_calc_partial_result (char p_char, char count){\n",
+    "  char *buff;\n",
+    "  int c = atoi(&count);\n",
+    "  if(c > 1){\n",
+    "    buff = (char*) malloc(sizeof(p_char) + sizeof(count));\n",
+    "    strcpy(buff, &p_char);\n",
+    "    strcat(buff, &count);\n",
+    "  }else{\n",
+    "    buff = (char*) malloc(sizeof(p_char));\n",
+    "    strncpy(buff, &p_char, sizeof(p_char));\n",
+    "  }\n",
+    "  return buff;\n",
+    "}\n"
+   ]
   }
  ],
  "metadata": {
+  "celltoolbar": "Edit Metadata",
   "kernelspec": {
    "display_name": "Python 2",
    "language": "python",
@@ -227,14 +296,14 @@
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    "codemirror_mode": {
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+    "version": 2
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    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.5.0"
+   "pygments_lexer": "ipython2",
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