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ShuffleAnArray.cpp
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59 lines (52 loc) · 1.63 KB
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// Source : https://leetcode.com/problems/shuffle-an-array/
// Author : Hao Chen
// Date : 2016-08-24
/***************************************************************************************
*
* 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();
***************************************************************************************/
class Solution {
public:
Solution(vector<int> nums) : _nums(nums), _solution(nums) {
srand(time(NULL));
}
/** Resets the array to its original configuration and return it. */
vector<int> reset() {
return _solution = _nums;
}
/** Returns a random shuffling of the array. */
vector<int> shuffle() {
//Fisher Yates
//https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
int i = _solution.size();
while ( --i > 0 ) {
int j = rand() % (i+1);
swap(_solution[i], _solution[j]);
}
return _solution;
}
private:
vector<int> _nums, _solution;
};
/**
* 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();
*/