标签：
Example:
// Init an array with set 1, 2, and 3.
int[] nums = {1,2,3};
Solution solution = new Solution(nums);
// Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must equally likely to be returned.
solution.shuffle();
// Resets the array back to its original configuration [1,2,3].
solution.reset();
// Returns the random shuffling of array [1,2,3].
solution.shuffle();
Solution: think about how you shuffle a deck of cards. You pick a card, and use it as the first/last card, then pick a second one, use it as a second/second last one.......
public class Solution { private int[] orig = null; private int[] current = null; private Random random = new Random(); public Solution(int[] nums) { this.orig = nums; this.current = nums.clone(); } /** * Resets the array to its original configuration and return it. */ public int[] reset() { return orig; } /** * Returns a random shuffling of the array. */ public int[] shuffle() { for (int i = 0; i < current.length; ++i) { int pick = random.nextInt(current.length); int swap = current.length - 1 - i; int temp = current[swap]; current[swap] = current[pick]; current[pick] = temp; } return current; } } /** * Your Solution object will be instantiated and called as such: * Solution obj = new Solution(nums); * int[] param_1 = obj.reset(); * int[] param_2 = obj.shuffle(); */
标签：
原文地址：http://www.cnblogs.com/neweracoding/p/5763839.html
