diff --git a/arrays_strings/compress/compress_solution.ipynb b/arrays_strings/compress/compress_solution.ipynb index aa11798..c1c5afc 100644 --- a/arrays_strings/compress/compress_solution.ipynb +++ b/arrays_strings/compress/compress_solution.ipynb @@ -18,7 +18,7 @@ "cell_type": "markdown", "metadata": {}, "source": [ - "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3B1C2D4'. Only compress the string if it saves space.\n", + "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3BCCD4'. Only compress the string if it saves space.\n", "\n", "* [Constraints](#Constraints)\n", "* [Test Cases](#Test-Cases)\n", @@ -51,7 +51,7 @@ "* None -> None\n", "* '' -> ''\n", "* 'AABBCC' -> 'AABBCC'\n", - "* 'AAABCCDDDD' -> 'A3B1C2D4'" + "* 'AAABCCDDDD' -> 'A3BCCD4'" ] }, { @@ -69,10 +69,20 @@ " * For each char in string\n", " * If char is the same as last_char, increment count\n", " * Else\n", - " * Append last_char to compressed_string\n", - " * append count to compressed_string\n", - " * count = 1\n", - " * last_char = char\n", + " * If the count is more than 2\n", + " * Append last_char to compressed_string\n", + " * append count to compressed_string\n", + " * count = 1\n", + " * last_char = char\n", + " * If count is 1\n", + " * Append last_char to compressed_string\n", + " * count = 1\n", + " * last_char = char\n", + " * If count is 2\n", + " * Append last_char to compressed_string\n", + " * Append last_char to compressed_string once more\n", + " * count = 1\n", + " * last_char = char\n", " * Append last_char to compressed_string\n", " * Append count to compressed_string\n", " * Return compressed_string\n", @@ -91,47 +101,66 @@ }, { "cell_type": "code", - "execution_count": 1, + "execution_count": 14, "metadata": { "collapsed": false }, "outputs": [], "source": [ "def compress_string(string):\n", - " if string is None or len(string) == 0:\n", - " return string\n", + "\tif string is None or len(string) == 0:\n", + "\t\treturn string\n", "\n", - " # Calculate the size of the compressed string\n", - " size = 0\n", - " last_char = string[0]\n", - " for char in string:\n", - " if char != last_char:\n", - " size += 2\n", - " last_char = char\n", - " size += 2\n", + "\t# Calculate the size of the compressed string\n", + "\tsize = 0\n", + "\tlast_char = string[0]\n", + "\tfor char in string:\n", + "\t\tif char != last_char:\n", + "\t\t\tsize += 2\n", + "\t\t\tlast_char = char\n", + "\tsize += 2\n", "\n", - " # If the compressed string size is greater than\n", - " # or equal to string size, return original string\n", - " if size >= len(string):\n", - " return string\n", + "\t# If the compressed string size is greater than\n", + "\t# or equal to string size, return original string\n", + "\tif size >= len(string):\n", + "\t\treturn string\n", "\n", - " # Create compressed_string\n", - " compressed_string = list()\n", - " count = 0\n", - " last_char = string[0]\n", - " for char in string:\n", - " if char == last_char:\n", - " count += 1\n", - " else:\n", - " compressed_string.append(last_char)\n", - " compressed_string.append(str(count))\n", - " count = 1\n", - " last_char = char\n", - " compressed_string.append(last_char)\n", - " compressed_string.append(str(count))\n", + "\t# Create compressed_string\n", + "\t# New objective:\n", + "\t\t# Single characters are to be left as is\n", + "\t\t# Double characters are to be left as are\n", + "\tcompressed_string = list()\n", + "\tcount = 0\n", + "\tlast_char = string[0]\n", + "\tfor char in string:\n", + "\t\tif char == last_char:\n", + "\t\t\tcount += 1\n", + "\t\telse:\n", + "\t\t\t# Do the old compression tricks only if count exceeds two\n", + "\t\t\tif count > 2:\n", + "\t\t\t\tcompressed_string.append(last_char)\n", + "\t\t\t\tcompressed_string.append(str(count))\n", + "\t\t\t\tcount = 1\n", + "\t\t\t\tlast_char = char\n", + "\t\t\t# If count is either 1 or 2 (or 0?)\n", + "\t\t\t# FIXME: CAN COUNT BE 0?\n", + "\t\t\telse:\n", + "\t\t\t\t# If count is 1, leave the char as is\n", + "\t\t\t\tif count == 1:\n", + "\t\t\t\t\tcompressed_string.append(last_char)\n", + "\t\t\t\t\tcount = 1\n", + "\t\t\t\t\tlast_char = char\n", + "\t\t\t\t# If count is 2, append the character twice\n", + "\t\t\t\telse:\n", + "\t\t\t\t\tcompressed_string.append(last_char)\n", + "\t\t\t\t\tcompressed_string.append(last_char)\n", + "\t\t\t\t\tcount = 1\n", + "\t\t\t\t\tlast_char = char\n", + "\tcompressed_string.append(last_char)\n", + "\tcompressed_string.append(str(count))\n", "\n", - " # Convert the characters in the list to a string\n", - " return \"\".join(compressed_string)" + "\t# Convert the characters in the list to a string\n", + "\treturn \"\".join(compressed_string)" ] }, { @@ -143,7 +172,7 @@ }, { "cell_type": "code", - "execution_count": 2, + "execution_count": 15, "metadata": { "collapsed": false }, @@ -167,7 +196,7 @@ " assert_equal(func(None), None)\n", " assert_equal(func(''), '')\n", " assert_equal(func('AABBCC'), 'AABBCC')\n", - " assert_equal(func('AAABCCDDDD'), 'A3B1C2D4')\n", + " assert_equal(func('AAABCCDDDD'), 'A3BCCD4')\n", " print('Success: test_compress')\n", "\n", "\n", @@ -182,7 +211,7 @@ }, { "cell_type": "code", - "execution_count": 3, + "execution_count": 16, "metadata": { "collapsed": false }, @@ -198,25 +227,34 @@ "source": [ "%run -i test_compress.py" ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], + "source": [] } ], "metadata": { "kernelspec": { - "display_name": "Python 2", + "display_name": "Python 3", "language": "python", - "name": "python2" + "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", - "version": 2 + "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", - "pygments_lexer": "ipython2", - "version": "2.7.10" + "pygments_lexer": "ipython3", + "version": "3.4.3" } }, "nbformat": 4, diff --git a/arrays_strings/compress/test_compress.py b/arrays_strings/compress/test_compress.py index 7ce5142..c527360 100644 --- a/arrays_strings/compress/test_compress.py +++ b/arrays_strings/compress/test_compress.py @@ -7,7 +7,7 @@ class TestCompress(object): assert_equal(func(None), None) assert_equal(func(''), '') assert_equal(func('AABBCC'), 'AABBCC') - assert_equal(func('AAABCCDDDD'), 'A3B1C2D4') + assert_equal(func('AAABCCDDDD'), 'A3BCCD4') print('Success: test_compress')