384 打乱数组

https://leetcode.cn/leetbook/read/top-interview-questions-easy/xn6gq1/

https://leetcode.cn/problems/shuffle-an-array/description/

cost: 12m26s

class Solution {
public:
    Solution(vector<int>& nums) {
        this->nums_ = nums;
        std::random_device rd;
        this->gen_ = std::mt19937(rd());
        this->dis_ = std::uniform_int_distribution<>(0, this->nums_.size() - 1);
    }

    vector<int> reset() { return this->nums_; }

    vector<int> shuffle() {
        vector<int> nums = this->nums_;
        for (int i = 0; i < nums.size(); i++) {
            int n = this->dis_(this->gen_);
            std::swap(nums[i], nums[n]);
        }
        return nums;
    }

private:
    vector<int> nums_;
    std::uniform_int_distribution<> dis_;
    std::mt19937 gen_;
};

/**
 * 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();
 */

• 时间复杂度：O(n)
• 空间复杂度：O(n)