Given an integer array nums, design an algorithm to randomly shuffle the array.
Implement the Solution class:
- Solution(int[] nums) Initializes the object with the integer array nums.
- 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 <= 200
- -106 <= nums[i] <= 106
- All the elements of nums are unique.
- At most 5 * 104 calls will be made to reset and shuffle.
class Solution {
private int[] origianl = null;
public Solution(int[] nums) {
origianl = nums;
}
/** Resets the array to its original configuration and return it. */
public int[] reset() {
return origianl;
}
/** Returns a random shuffling of the array. */
public int[] shuffle() {
// copy the orginal array
int[] copy = origianl.clone();
Random random = new Random();
for(int i=0;i<copy.length;i++){
// find random index in the array
int index = random.nextInt(arr.length);
// swap current element with random
int temp = copy[i];
copy[i] = copy[index];
copy[index] = temp;
}
return copy;
}
}
/**
* 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();
*/