384 Shuffle an Array 打乱数组

打乱一个没有重复元素的数组。
示例:
// 以数字集合 1, 2 和 3 初始化数组。
int[] nums = {1,2,3};
Solution solution = new Solution(nums);
// 打乱数组 [1,2,3] 并返回结果。任何 [1,2,3]的排列返回的概率应该相同。
solution.shuffle();
// 重设数组到它的初始状态[1,2,3]。
solution.reset();

详见：https://leetcode.com/problems/shuffle-an-array/description/

C++：

class Solution {
public:
    Solution(vector<int> nums) {
        vec=nums;
    }

    /** Resets the array to its original configuration and return it. */
    vector<int> reset() {
        return vec;
    }

    /** Returns a random shuffling of the array. */
    vector<int> shuffle() {
        vector<int> res=vec;
        for(int i=0;i<vec.size();++i)
        {
            int t=i+rand()%(vec.size()-i);
            swap(res[i],res[t]);
        }
        return res;
    }
private:
    vector<int> vec;
};

/**
 * Your Solution object will be instantiated and called as such:
 * Solution obj = new Solution(nums);
 * vector<int> param_1 = obj.reset();
 * vector<int> param_2 = obj.shuffle();
 */

参考：https://www.cnblogs.com/grandyang/p/5783392.html