✨ Code for Chapter 1 - 10 (careercup#12)

* (attempt) 1.1 - 1.4

* (cleanup) modify readme

* (cleanup) tidy up checkboxes

* (attempt) 1.5 - 1.8

* (attempt)

* (cleanup) delete questions

* (attempt) 1.9 - stringRotation

* (attempt) 2.1 - removeDups

* (attempt) return Kth to last

* (attempt) deleteMiddleNode

* (cleanup) cleanup comments in 1.9 - 2.3

* (attempt) 2.4

* (attempt) 2.5

* (attempt) 2.6

* (attempt) 2.7

* (attempt) 2.8, 3.1, 3.2

* (cleanup) tidy up package.json and readme.md file

* (attempt) 3.3 - 3.5

* (attempt) 3.6, 4.01 - 4.03

* (cleanup) tidy up package.json

* (revamp) clean out previously existing files

* (migrate) move over and tidy up tests in js files. clean up readme

* (readme) minor edits

* (readme) minor edits

* (readme) minor edits

* (readme) minor edits

* (readme) minor edits

* (package.json) amend author, licence, and add eslint

* (package.json) add eslint in test script, move eslint to dev
dependencies

Author: Tony K. Tan

README.md

@@ -1,53 +1,142 @@
 # Cracking the Coding Interview 6th Edition - JavaScript
 
-<br>
+## Instructions
 
-## Question List:
-
-#### Chapter 1
-- [x] 1.1 - [Is Unique](lib/data-structures/chapter-1/1_1.js)
-- [x] 1.2 - [Check Permutation](lib/data-structures/chapter-1/1_2.js)
-- [x] 1.3 - [URLify](lib/data-structures/chapter-1/1_3.js)
-- [x] 1.4 - [Palindrome Permutation](lib/data-structures/chapter-1/1_4.js)
-- [x] 1.5 - [One Away](lib/data-structures/chapter-1/1_5.js)
-- [x] 1.6 - [String Compression](lib/data-structures/chapter-1/1_6.js)
-- [x] 1.7 - [Rotate Matrix](lib/data-structures/chapter-1/1_7.js)
-- [x] 1.8 - [Zero Matrix](lib/data-structures/chapter-1/1_8.js)
-- [ ] 1.9 - String Rotation
-
-#### Chapter 2
-- [x] 2.1 - [Remove Duplicate](lib/data-structures/chapter-2/2_1.js)
-- [x] 2.2 - [Return Kth to Last](lib/data-structures/chapter-2/2_2.js)
-- [x] 2.3 - [Delete Middle Node](lib/data-structures/chapter-2/2_3.js)
-- [x] 2.8 - [Detection Loop](lib/data-structures/chapter-2/2_8.js)
-
-
-#### Chapter 3
-- [ ] 3.1 - Three in One
-- [ ] 3.2 - Stack Min
-- [ ] 3.3 - Stack of Plates
-- [ ] 3.4 - Queue via Stacks
-- [x] 3.5 - [Sort Stack](lib/data-structures/chapter-3/3_5.js)
-- [ ] 3.6 - Animal Shelter
+- This repository contains JavaScript attempts on questions listed in the book.
 
-<br>
+- So far, code or short writeups are available for the first 10 chapters.
 
-## Install dependencies:
-```bash
-npm install
-```
+- At Gayle's request, the files only contain code, and do not contain the actual questions. For the questions, please support Gayle by purchasing the [book](https://www.amazon.com/Cracking-Coding-Interview-Programming-Questions/dp/0984782850).
+
+- Under each JavaScript file, there are tests to check that the code is working as expected. For convenience, simple logging is used to test the functions. To run the tests, just cd into the folder containing the .js file and run `node <fileName>.js` to run the tests.
+
+- Contributions welcome
+
+## List of Coding Questions:
+
+#### Chapter 1 
+- [x] 1.1 - Is Unique
+- [x] 1.2 - Check Permutation
+- [x] 1.3 - URLify
+- [x] 1.4 - Palindrome Permutation
+- [x] 1.5 - One Away
+- [x] 1.6 - String Compression
+- [x] 1.7 - Rotate Matrix
+- [x] 1.8 - Zero Matrix
+- [x] 1.9 - String Rotation 
+
+#### Chapter 2 
+- [x] 2.1 - Remove Dups
+- [x] 2.2 - Return Kth to Last
+- [x] 2.3 - Delete Middle Node
+- [x] 2.4 - Partition
+- [x] 2.5 - Sum Lists
+- [x] 2.6 - Palindrome
+- [x] 2.7 - Intersection
+- [x] 2.8 - Loop Detection
+
+#### Chapter 3 
+- [x] 3.1 - Three in One
+- [x] 3.2 - Stack Min
+- [x] 3.3 - Stack of Plates
+- [x] 3.4 - Queue via Stacks
+- [x] 3.5 - Sort Stack
+- [x] 3.6 - Animal Shelter
+
+#### Chapter 4
+- [x] 4.1 - Route Between Nodes
+- [x] 4.2 - Minimal Tree
+- [x] 4.3 - List of Depths
+- [x] 4.4 - Check Balanced
+- [x] 4.5 - Validate BST
+- [x] 4.6 - Successor
+- [x] 4.7 - Build Order
+- [x] 4.8 - First Common Ancestor
+- [x] 4.9 - BST Sequences
+- [x] 4.10 - Check Subtree
+- [x] 4.11 - Random Node
+- [x] 4.12 - Paths with Sum
+
+#### Chapter 5
+- [x] 5.1 - Insertion
+- [x] 5.2 - Binary to String
+- [x] 5.3 - Flip Bit To Win
+- [x] 5.4 - Next Number
+- [x] 5.5 - Debugger
+- [x] 5.6 - Conversion
+- [x] 5.7 - Pairwise Swap
+- [x] 5.8 - Draw Line
+
+#### Chapter 6
+- [x] 6.1 - Heavy Pill
+- [x] 6.2 - Basketball
+- [x] 6.3 - Dominos
+- [x] 6.4 - Ants on a Triangle
+- [x] 6.5 - Jugs of Water
+- [x] 6.6 - Blue-Eyed Island
+- [x] 6.7 - The Apocalypse
+- [x] 6.8 - The Egg Drop Problem
+- [x] 6.9 - 100 Lockers
+- [x] 6.10 - Poison
+
+#### Chapter 7
+- [x] 7.1 - Deck of Cards
+- [x] 7.2 - Call Center
+- [x] 7.3 - Jukebox
+- [x] 7.4 - Parking Lot
+- [x] 7.5 - Online Book Reader
+- [x] 7.6 - Jigsaw
+- [x] 7.7 - Chat Server
+- [x] 7.8 - Othello
+- [x] 7.9 - Circular Array
+- [x] 7.10 - Minesweeper
+- [x] 7.11 - File System
+- [x] 7.12 - Hash Table
+
+#### Chapter 8
+- [x] 8.1 - Triple Step
+- [x] 8.2 - Robot in a Grid
+- [x] 8.3 - Magic Index
+- [x] 8.4 - Power Set
+- [x] 8.5 - Recursive Multiply
+- [x] 8.6 - Towers of Hanoi
+- [x] 8.7 - Permutations without Dups
+- [x] 8.8 - Permutations with Dups
+- [x] 8.9 - Parens
+- [x] 8.10 - Paint Fill
+- [x] 8.11 - Coins
+- [x] 8.12 - Eight Queens
+- [x] 8.13 - Stack Boxes
+- [x] 8.14 - Boolean Eval
+
+#### Chapter 9
+- [x] 9.1 - Stock Data
+- [x] 9.2 - Social Network
+- [x] 9.3 - Web Crawler
+- [x] 9.4 - Duplicate URLs
+- [x] 9.5 - Cache
+- [x] 9.6 - Sales Rank
+- [x] 9.7 - Personal Financial Manager
+- [x] 9.8 - Paste Bin
+
+#### Chapter 10
+- [x] 10.1 - Sorted Merge
+- [x] 10.2 - Group Anagrams
+- [x] 10.3 - Search In Rotated Array
+- [x] 10.4 - Sorted Search No Size
+- [x] 10.5 - Sparse Search
+- [x] 10.6 - Sort Big File
+- [x] 10.7 - Missing Int
+- [x] 10.8 - Find Duplicates
+- [x] 10.9 - Sorted Matrix Search
+- [x] 10.10 - Rank From Stream
+- [x] 10.11 - Peaks And Valleys
 
 <br>
 
 ## Test
 
-```bash
+```sh
 npm test
 ```
 
-If you just want to lint
-```bash
-npm run lint
-```
-
-<br>

chapter01/1.1 - Is Unique/isUnique.js

@@ -0,0 +1,16 @@
+var allUniqueChars = function(string) {
+  
+  // O(n^2) approach, no additional data structures used
+  // for each character, check remaining characters for duplicates
+  for (var i = 0; i < string.length; i++) {
+    for (var j = i + 1; j < string.length; j++) {
+      if (string[i] === string[j]) {
+        return false; // if match, return false
+      }
+    }
+  }
+  return true; // if no match, return true
+};
+
+/* TESTS */
+// log some tests here

chapter01/1.2 - Check Perm/checkPermute.js

@@ -0,0 +1,19 @@
+var checkPermute = function(stringOne, stringTwo) {
+  // if different lengths, return false
+  if (stringOne.length !== stringTwo.length) {
+    return false;
+  // else sort and compare 
+  // (doesnt matter how it's sorted, as long as it's sorted the same way)
+  } else {
+    var sortedStringOne = stringOne.split('').sort().join('');
+    var sortedStringTwo = stringTwo.split('').sort().join('');
+    return sortedStringOne === sortedStringTwo;
+  }
+};
+
+// Tests
+console.log(checkPermute('aba', 'aab'), true);
+
+console.log(checkPermute('aba', 'aaba'), false);
+
+console.log(checkPermute('aba', 'aa'), false);

chapter01/1.3 - URLify/urlify.js

@@ -0,0 +1,24 @@
+var urlify = function(str, length) {
+  // have a pointer to check from start to end
+  var strArr = str.split('');
+  var pointer = 0;
+  while (pointer < str.length) {
+    if (strArr[pointer] === ' ') {
+      // *** needs more work here, a little wierd
+      // not handling trailing spaces properly
+      for (var i = str.length - 1; i > pointer + 3; i--) {
+        strArr[i] = str[i - 2];
+      }
+      strArr[pointer] = '%';
+      strArr[pointer+1] = '2';
+      strArr[pointer+2] = '0';
+      console.log(strArr, strArr.length);
+    } 
+    pointer++;
+  }
+  // if character is a space, move remainder chars by two
+  // replace following three chars with '%20'
+  return strArr.join('');
+};
+
+console.log(urlify('Mr John Smith    ', 13), 'Mr%20John%20Smith');

chapter01/1.4 - PalinPerm/palinPerm.js

@@ -0,0 +1,34 @@
+var palinPerm = function(string) {
+  // create object literal to store charcount
+  var chars = {};
+  var currChar;
+  var mulligan = false;
+  var isPerm = true;
+  // pump characters in, spaces not counted, all lowercase
+  string.split('').forEach((char) => {
+    if (char !== ' ') {
+      currChar = char.toLowerCase();
+      if (chars[currChar] === undefined) {
+        chars[currChar] = 0;
+      }
+      chars[currChar]++;
+    }
+  });
+  // check that all chars are even count, except for one exception
+  Object.keys(chars).forEach((char) => {
+    if (chars[char] % 2 > 0) {
+    // if more than one exception, return false
+      if (mulligan) {
+        isPerm = false; // return in a forEach statment doesn't flow out of function scope
+      } else {
+        mulligan = true;
+      }
+    }
+  });
+  // if not return true
+  return isPerm;
+};
+
+// TESTS
+console.log(palinPerm('Tact Coa'), 'true');
+console.log(palinPerm('Tact boa'), 'false');

chapter01/1.5 - OneAway/oneAway.js

@@ -0,0 +1,64 @@
+var oneAway = function(string1, string2) {
+  // insert a char for str1 -> remove a char for str2
+  var checkOneMissing = function(first, second) {
+    if (first.length !== second.length - 1) {
+      return false;
+    } else {
+      var mulligan = false;
+      var fP = 0; // first Pointer
+      var sP = 0; // second Pointer
+      while (fP < first.length) {
+        if (first[fP] !== second[sP]) {
+          if (mulligan) {
+            return false;
+          } else {
+            mulligan = true;
+            sP++; // second length is longer
+          }
+        } else {
+          fP++;
+          sP++;
+        }
+      }
+      return true;
+    }
+  };
+
+  var checkOneDiff = function(first, second) {
+    if (first.length !== second.length) {
+      return false;
+    } else {
+      var mulligan = false;
+      var fP = 0; // first Pointer
+      var sP = 0; // second Pointer
+      while (fP < first.length) {
+        if (first[fP] !== second[sP]) {
+          if (mulligan) {
+            return false; // more than one mismatch
+          } else {
+            mulligan = true; // use up mulligan
+          }
+        }
+        fP++;
+        sP++;
+      }
+      return true;
+    }
+  };
+  // insert a char for str1 -> remove a char for str2
+  // check one diff
+
+  // console log checks
+  // console.log(string1, string2, 'checkMiss', checkOneMissing(string1, string2));
+  // console.log(string2, string1, 'checkMiss', checkOneMissing(string2, string1));
+  // console.log(string1, string2, 'checkDiff', checkOneDiff(string1, string2));
+
+  return checkOneMissing(string1, string2) || checkOneMissing(string2, string1) || checkOneDiff(string1, string2);
+};
+
+
+// Test
+console.log(oneAway('pale', 'ple'), true);
+console.log(oneAway('pales', 'pale'), true);
+console.log(oneAway('pale', 'bale'), true);
+console.log(oneAway('pale', 'bake'), false);

chapter01/1.6 - String Compression/strComp.js

@@ -0,0 +1,25 @@
+var strComp = function(string) {
+  var compressed = '';
+  var currChar = '';
+  var currCount = '';
+  var maxCount = 1;
+  for (var i = 0; i < string.length; i++) {
+    if (currChar !== string[i]) {
+      console.log(currChar, string[i], i);
+      compressed = compressed + currChar + currCount;
+      maxCount = Math.max(maxCount, currCount);
+      currChar = string[i];
+      currCount = 1;
+    } else {
+      currCount++;
+    }
+  }
+  compressed = compressed + currChar + currCount;
+  maxCount = Math.max(maxCount, currCount);
+
+  return maxCount === 1 ? string : compressed;
+};
+
+// Test
+console.log('aaaaaa', strComp('aaaaaa'), 'a6');
+console.log('aabcccccaaa', strComp('aabcccccaaa'), 'a2b1c5a3');