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();
public class Solution { int[] originArray; int[] suffleArray; public Solution(int[] nums) { this.originArray = nums; this.suffleArray = Arrays.copyOf(nums, nums.length); // Or nums.clone() 不能单纯取等号 } /** Resets the array to its original configuration and return it. */ public int[] reset() { return originArray; } /** Returns a random shuffling of the array. */ public int[] shuffle() { for(int i = 0 ; i < suffleArray.length ; i++){ int n = generateRandom(); swap(i,n); } return suffleArray; } public void swap (int a, int b){ int temp = suffleArray[a]; suffleArray[a] = suffleArray[b]; suffleArray[b] = temp; } public int generateRandom(){ Random r = new Random(); int n = r.nextInt(suffleArray.length); return n; } } /** * Your Solution object will be instantiated and called as such: * Solution obj = new Solution(nums); * int[] param_1 = obj.reset(); * int[] param_2 = obj.shuffle(); */
时间: 2024-10-12 02:46:29