- Difficulty: Medium
- Tags: LeetCode, Medium, Array, Math, Randomized, leetcode-384, O(n), EPI
Problem
Given an integer array nums
, design an algorithm to randomly shuffle the array. All permutations of the array should be equally likely as a result of the shuffling.
Implement the Solution
class:
Solution(int[] nums)
Initializes the object with the integer arraynums
.int[] reset()
Resets the array to its original configuration and returns it.int[] shuffle()
Returns a random shuffling of the array.
Example 1:
Input ["Solution", "shuffle", "reset", "shuffle"] [[[1, 2, 3]], [], [], []] Output [null, [3, 1, 2], [1, 2, 3], [1, 3, 2]] Explanation Solution solution = new Solution([1, 2, 3]); solution.shuffle(); // Shuffle the array [1,2,3] and return its result. // Any permutation of [1,2,3] must be equally likely to be returned. // Example: return [3, 1, 2] solution.reset(); // Resets the array back to its original configuration [1,2,3]. Return [1, 2, 3] solution.shuffle(); // Returns the random shuffling of array [1,2,3]. Example: return [1, 3, 2]
Constraints:
1 <= nums.length <= 50
-106 <= nums[i] <= 106
- All the elements of
nums
are unique. - At most
104
calls in total will be made toreset
andshuffle
.