okuyan

/*
Find all unique triplets in the array which gives the sum of 0.
a + b + c = 0;

[-1, 0, 1, 2, -1, -4]  ==> [[-1, 0, 1], [-1, -1, 2]];

*/

var temp = [-1, 0, 1, 2, -1, -4];

okuyan

var createMapping = function(numbers) {
  
  var mapping = {},
      size = numbers.length;
  
  for (var i = 0; i < size; i++) {
      mapping[numbers[i]] = i;
  }
  
  return mapping;

okuyan

// Given an unsorted integer array, find the first missing positive integer
// For example,
// Given [1, 2, 0], return 3.
// Given [3, 4, -1, 1], return 2.


var firstMissingPositive = function(A){
  
  var i = 0;

okuyan

//Reverse digits of an integer
//Given x = 123, return 321
//Given x = -123, return -321

var reverse = function(x) {

  var lastDigit = 0,
      result = 0,
      isNeg = true;
  

okuyan

//Determine whether an integer is a palindrome. Do this without extra space.

var isPalindrome = function (x) {
    
  if (x < 0) {
    return false;    
  }
  
  //何桁で割ったら、1桁になるか
  var div = 1;

okuyan

//antipattern
var arr = new Array("apple", "google", "yahoo");

//the exact same array
var arr = ["apple", "google", "yahoo"];

console.log(typeof arr); // "object"
console.log(arr.constructor === Array); // true

okuyan

var arr = new Array(2, 3, 4);
console.log(arr);  // [2, 3, 4]

var arr2 = new Array(2);
console.log(arr2); // [undefined, undefined] ew...
console.log(arr2.length); //2

// using array literal 
var a = [3.14]; 
console.log( a[ 0]); // 3.14 

okuyan

//javascript php foreach equivalent
var obj = {prop1: 5, prop2: 13, prop3: 8};

for (var item in obj) {
  console.log(item + ':' + obj[item]);
}

okuyan

  var parseQueryString = function(queryString) {
     var params = {},
       queries, temp, i, l;
  
       queries = queryString.split('&');
       l = queries.length;
  
       for (i = 0; i < l; i++) {
         temp = queries[i].split('=');

okuyan

//before
for (var i = 0, max = myarray.length; i < max; i + +) { 
  // do something with myarray[ i] 
}

//after
var i, myarray = [];

for (i = myarray.length; i--) {
  // do somthing with myarray[i]