#2576
Find the Maximum Number of Marked Indices
specialist · 995 · lc medium +32 · verified · 41.1% accepted · 597 likes · top 21%
Description
Given a 0-indexed integer array nums with all indices initially unmarked, repeatedly pick two distinct unmarked indices i and j satisfying 2 * nums[i] <= nums[j] and mark both. Return the maximum total number of marked indices achievable.
Example 1:
Input: nums = [3,5,2,4]
Output: 2
Explanation: In the first operation: pick i = 2 and j = 1, the operation is allowed because 2 * nums[2] <= nums[1]. Then mark index 2 and 1.
It can be shown that there's no other valid operation so the answer is 2.
Example 2:
Input: nums = [9,2,5,4]
Output: 4
Explanation: In the first operation: pick i = 3 and j = 0, the operation is allowed because 2 * nums[3] <= nums[0]. Then mark index 3 and 0.
In the second operation: pick i = 1 and j = 2, the operation is allowed because 2 * nums[1] <= nums[2]. Then mark index 1 and 2.
Since there is no other operation, the answer is 4.
Example 3:
Input: nums = [7,6,8]
Output: 0
Explanation: There is no valid operation to do, so the answer is 0.
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