384. Shuffle an Array

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

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 {
    vector<int> nums;
public:
    Solution(vector<int>& nums) {
        this->nums = nums;
    }
    
    /** Resets the array to its original configuration and return it. */
    vector<int> reset() {
        return this->nums;
    }
    
    /** Returns a random shuffling of the array. */
    vector<int> shuffle() {
        vector<int> dump(nums);
        vector<int> shuffled;
        shuffled.reserve(nums.size());
        for (int i = dump.size() - 1; i >= 0; --i) {
            int index = rand() % (i + 1);
            shuffled.push_back(dump[index]);
            int temp = dump[index];
            dump[index] = dump[i];
            dump[i] = temp;
        }
        return shuffled;
    }
};

/**
 * 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();
 */