Shuffle an Array

Author: lessfish

Algorithms/Shuffle an Array/shuffle-an-array.js

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+// Source : https://leetcode.com/problems/shuffle-an-array/
+// Author : Han Zichi
+// Date   : 2017-01-23
+
+/**
+ * @param {number[]} nums
+ */
+var Solution = function(nums) {
+  this.nums = nums;
+};
+
+/**
+ * Resets the array to its original configuration and return it.
+ * @return {number[]}
+ */
+Solution.prototype.reset = function() {
+  return this.nums;
+};
+
+/**
+ * Returns a random shuffling of the array.
+ * @return {number[]}
+ */
+Solution.prototype.shuffle = function() {
+  // @see https://github.com/hanzichi/underscore-analysis/issues/15
+  function shuffle(a) {
+    var length = a.length;
+    var shuffled = Array(length);
+
+    for (var index = 0, rand; index < length; index++) {
+      rand = ~~(Math.random() * (index + 1));
+      if (rand !== index)
+        shuffled[index] = shuffled[rand];
+      shuffled[rand] = a[index];
+    }
+
+    return shuffled;
+  }
+
+  return shuffle(this.nums);
+};
+
+/**
+ * Your Solution object will be instantiated and called as such:
+ * var obj = Object.create(Solution).createNew(nums)
+ * var param_1 = obj.reset()
+ * var param_2 = obj.shuffle()
+ */