nums.

int pick(int target) Picks a random index i from nums where nums[i] == target. If there are multiple valid i's, then each index should have an equal probability of returning.

Example 1:

Input
["Solution", "pick", "pick", "pick"]
[[[1, 2, 3, 3, 3]], [3], [1], [3]]
Output
[null, 4, 0, 2]

Explanation
Solution solution = new Solution([1, 2, 3, 3, 3]);
solution.pick(3); // It should return either index 2, 3, or 4 randomly. Each index should have equal probability of returning.
solution.pick(1); // It should return 0. Since in the array only nums[0] is equal to 1.
solution.pick(3); // It should return either index 2, 3, or 4 randomly. Each index should have equal probability of returning.

Constraints:

1 <= nums.length <= 2 * 10⁴
-2³¹ <= nums[i] <= 2³¹ - 1
target is an integer from nums.
At most 10⁴ calls will be made to pick.

23:T4e4,Given an integer array `nums` with possible **duplicates** , randomly output the index of a given `target` number. You can assume that the given target number must exist in the array. Implement the `Solution` class: * `Solution(int[] nums)` Initializes the object with the array `nums`. * `int pick(int target)` Picks a random index `i` from `nums` where `nums[i] == target`. If there are multiple valid i's, then each index should have an equal probability of returning. **Example 1:** **Input** ["Solution", "pick", "pick", "pick"] [[[1, 2, 3, 3, 3]], [3], [1], [3]] **Output** [null, 4, 0, 2] **Explanation** Solution solution = new Solution([1, 2, 3, 3, 3]); solution.pick(3); // It should return either index

Random Pick Index

Problem Description

Problem Description

Answer Panel