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();
洗牌算法
C++（267ms）：
1 class Solution { 2 private: 3 vector<int> nums ; 4 public: 5 Solution(vector<int> nums) { 6 this->nums = nums ; 7 } 8 9 /** Resets the array to its original configuration and return it. */ 10 vector<int> reset() { 11 return nums ; 12 } 13 14 /** Returns a random shuffling of the array. */ 15 vector<int> shuffle() { 16 vector<int> res(nums) ; 17 int len = nums.size() ; 18 for(int i = len-1 ; i >= 0 ; i--){ 19 int pos = rand()%(i+1) ; 20 swap(res[pos] , res[i]) ; 21 } 22 return res ; 23 } 24 }; 25 26 /** 27 * Your Solution object will be instantiated and called as such: 28 * Solution obj = new Solution(nums); 29 * vector<int> param_1 = obj.reset(); 30 * vector<int> param_2 = obj.shuffle(); 31 */
1 class Solution { 2 private: 3 vector<int> nums ; 4 public: 5 Solution(vector<int> nums) { 6 this->nums = nums ; 7 } 8 9 /** Resets the array to its original configuration and return it. */ 10 vector<int> reset() { 11 return nums ; 12 } 13 14 /** Returns a random shuffling of the array. */ 15 vector<int> shuffle() { 16 vector<int> res(nums) ; 17 int len = nums.size() ; 18 for(int i = 0 ; i < len ; i++){ 19 int pos = i + rand()%(len-i) ; 20 swap(res[i], res[pos]) ; 21 } 22 return res ; 23 } 24 }; 25 26 /** 27 * Your Solution object will be instantiated and called as such: 28 * Solution obj = new Solution(nums); 29 * vector<int> param_1 = obj.reset(); 30 * vector<int> param_2 = obj.shuffle(); 31 */
