reverse a string

README.md

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+# AlgoCasts
+
+Companion repo to a course on Udemy.com

completed_exercises/anagrams/index.js

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+// --- Directions
+// Check to see if two provided strings are anagrams of eachother.
+// One string is an anagram of another if it uses the same characters
+// in the same quantity. Only consider characters, not spaces
+// or punctuation.  Consider capital letters to be the same as lower case
+// --- Examples
+//   anagrams('rail safety', 'fairy tales') --> True
+//   anagrams('RAIL! SAFETY!', 'fairy tales') --> True
+//   anagrams('Hi there', 'Bye there') --> False
+
+function anagrams(stringA, stringB) {
+  return cleanString(stringA) === cleanString(stringB);
+}
+
+function cleanString(str) {
+  return str
+    .replace(/[^\w]/g, '')
+    .toLowerCase()
+    .split('')
+    .sort()
+    .join('');
+}
+
+module.exports = anagrams;
+
+// function anagrams(stringA, stringB) {
+//   const aCharMap = buildCharMap(stringA);
+//   const bCharMap = buildCharMap(stringB);
+//
+//   if (Object.keys(aCharMap).length !== Object.keys(bCharMap).length) {
+//     return false;
+//   }
+//
+//   for (let char in aCharMap) {
+//     if (aCharMap[char] !== bCharMap[char]) {
+//       return false;
+//     }
+//   }
+//
+//   return true;
+// }
+//
+// function buildCharMap(str) {
+//   const charMap = {};
+//
+//   for (let char of str.replace(/[^\w]/g, '').toLowerCase()) {
+//     charMap[char] = charMap[char] + 1 || 1;
+//   }
+//
+//   return charMap;
+// }

completed_exercises/bst/index.js

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+// --- Directions
+// 1) Implement the Node class to create
+// a binary search tree.  The constructor
+// should initialize values 'data', 'left',
+// and 'right'.
+// 2) Implement the 'insert' method for the
+// Node class.  Insert should accept an argument
+// 'data', then create an insert a new node
+// at the appropriate location in the tree.
+// 3) Implement the 'contains' method for the Node
+// class.  Contains should accept a 'data' argument
+// and return the Node in the tree with the same value.
+// If the value isn't in the tree return null.
+
+class Node {
+  constructor(data) {
+    this.data = data;
+    this.left = null;
+    this.right = null;
+  }
+
+  insert(data) {
+    if (data < this.data && this.left) {
+      this.left.insert(data);
+    } else if (data < this.data) {
+      this.left = new Node(data);
+    } else if (data > this.data && this.right) {
+      this.right.insert(data);
+    } else if (data > this.data) {
+      this.right = new Node(data);
+    }
+  }
+
+  contains(data) {
+    if (this.data === data) {
+      return this;
+    }
+
+    if (this.data < data && this.right) {
+      return this.right.contains(data);
+    } else if (this.data > data && this.left) {
+      return this.left.contains(data);
+    }
+
+    return null;
+  }
+}
+
+module.exports = Node;

completed_exercises/bst/test.js

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+const Node = require('./index');
+
+test('Node is a constructor', () => {
+  expect(typeof Node.prototype.constructor).toEqual('function');
+});
+
+test('Node can insert correctly', () => {
+  const node = new Node(10);
+  node.insert(5);
+  node.insert(15);
+  node.insert(17);
+
+  expect(node.left.data).toEqual(5);
+  expect(node.right.data).toEqual(15);
+  expect(node.right.right.data).toEqual(17);
+});
+
+test('Contains returns node with the same data', () => {
+  const node = new Node(10);
+  node.insert(5);
+  node.insert(15);
+  node.insert(20);
+  node.insert(0);
+  node.insert(-5);
+  node.insert(3);
+
+  const three = node.left.left.right;
+  expect(node.contains(3)).toEqual(three);
+});
+
+test('Contains returns null if value not found', () => {
+  const node = new Node(10);
+  node.insert(5);
+  node.insert(15);
+  node.insert(20);
+  node.insert(0);
+  node.insert(-5);
+  node.insert(3);
+
+  expect(node.contains(9999)).toEqual(null);
+});

completed_exercises/capitalize/index.js

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+// --- Directions
+// Write a function that accepts a string.  The function should
+// capitalize the first letter of each word in the string then
+// return the capitalized string.
+// --- Examples
+//   capitalize('a short sentence') --> 'A Short Sentence'
+//   capitalize('a lazy fox') --> 'A Lazy Fox'
+//   capitalize('look, it is working!') --> 'Look, It Is Working!'
+
+function capitalize(str) {
+  let result = str[0].toUpperCase();
+
+  for (let i = 1; i < str.length; i++) {
+    if (str[i - 1] === ' ') {
+      result += str[i].toUpperCase();
+    } else {
+      result += str[i];
+    }
+  }
+
+  return result;
+}
+
+module.exports = capitalize;
+
+// function capitalize(str) {
+//   const words = [];
+//
+//   for (let word of str.split(' ')) {
+//     words.push(word[0].toUpperCase() + word.slice(1));
+//   }
+//
+//   return words.join(' ');
+// }