Code Challengees

codeChallenges.js

//1) reverse a string without using any variables or 
/*****************************************************/

function reverseString(s) {
    if (s === '')
        return '';
    else
        return s.slice(1) + s[0];
}

var reversed = reverseString('alexander');
console.log(reversed);

//2) Create a linkedList and write add, remove and reverse methods
/*****************************************************/

function LinkedList() {
    this.head = null;
}

LinkedList.prototype.makeNode = function(value) {
    var node = {};
    node.value = value;
    node.next = null;
    return node;
}

LinkedList.prototype.add = function(value) {
    var currentNode = this.makeNode(value);
    if (this.head === null) {
        this.head = currentNode;
    } else {
        var current = this.head;
        while (current.next) {
            current = current.next;
        }
        current.next = currentNode;
    }
}

LinkedList.prototype.remove = function(value) {
    var current = this.head;
    if (!current)
        return null;
    //if the head is the value to remove,
    //replace the head with the next node
    if (current.value === value) {
        this.head = current.next;
    }
    //else the node we are seeking is somewhere in the middle
    else {
        var previous = current;
        while (current) {
            if (current.value === value) {
                previous.next = current.next;
                break;
            }
            previous = current;
            current = current.next;
        }
    }
}

LinkedList.prototype.reverse = function() {
    var current = this.head;
    if (!current || !current.next)
        return this;
    else {
        var previous = null;
        var save;
        while (current) {
            save = current.next;
            current.next = previous;
            previous = current;
            current = save;
        }
        this.head = previous;
    }
    return this;
}

LinkedList.prototype.contains = function(value) {
    var current = this.head;
    if (!current) {
        return null
    } else {
        while (current) {
            if (current.value === value) {
                return true;
            }
            current = current.next;
        }
        return false;
    }
}

var list = new LinkedList();
list.add(10);
list.add(20);
list.add(30);
//list.remove(10);
console.log(list);
console.log(list.reverse());
console.log(list.contains(30));
console.log(list.contains(60));


//3) Given two sorted arrays, i.e. [1,2,3,4,8,20] and [2,4,4,8] 
//combine them into one sorted array
/*****************************************************/


//4) /return an array with the anagrams grouped together. Makes sure the anagrams are unique.
/*****************************************************/
var arr = ['cat', 'dog', 'tac', 'god', 'act'];

var allAnagrams = function(arr) {
    var anagrams = {};
    arr.forEach(function(str) {
        var recurse = function(ana, str) {
            if (str === '') {
                anagrams[ana] = 1;
            }
            for (var i = 0; i < str.length; i++) {
                console.log('STR[i]', str[i]);
                recurse(ana + str[i], str.slice(0, i) + str.slice(i + 1));
            }
        }
        recurse('', str);
    });
    return Object.keys(anagrams);
}

//5) check to see if a word a palindrome

var isPalindrome = function(word){
  var stack = '';
  var queue = '';
  for(var i = 0; i < word.length; i++){
    stack += word[i];
    queue += word[word.length - i - 1];
  }

  console.log(stack);
  console.log(queue);
  return stack === queue ? true : false; 
};

var result = isPalindrome('good');
console.log(result);