384. Shuffle an Array

@(leetcode)[数组]

Problem

Shuffle a set of numbers without duplicates.

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

class Solution {public:    Solution(vector<int> nums) : org(nums){    }    /** Resets the array to its original configuration and return it. */    vector<int> reset() {        return org;    }    /** Returns a random shuffling of the array. */    vector<int> shuffle() {        vector<int> ret = org;        int len = ret.size();        for(int i = 0; i < len; ++i) {            //随机从[i, n-1]中取一个数和i交换            int exchange_idx = rand() %(len - i);            swap(ret[i], ret[i + exchange_idx]);        }        return ret;    }private:    vector<int> org;};