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Formatted question description: https://leetcode.ca/all/2576.html

# 2576. Find the Maximum Number of Marked Indices

## Description

You are given a 0-indexed integer array nums.

Initially, all of the indices are unmarked. You are allowed to make this operation any number of times:

• Pick two different unmarked indices i and j such that 2 * nums[i] <= nums[j], then mark i and j.

Return the maximum possible number of marked indices in nums using the above operation any number of times.

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.



Constraints:

• 1 <= nums.length <= 105
• 1 <= nums[i] <= 109

## Solutions

• class Solution {
public int maxNumOfMarkedIndices(int[] nums) {
Arrays.sort(nums);
int n = nums.length;
int ans = 0;
for (int i = 0, j = (n + 1) / 2; j < n; ++i, ++j) {
while (j < n && nums[i] * 2 > nums[j]) {
++j;
}
if (j < n) {
ans += 2;
}
}
return ans;
}
}

• class Solution {
public:
int maxNumOfMarkedIndices(vector<int>& nums) {
sort(nums.begin(), nums.end());
int n = nums.size();
int ans = 0;
for (int i = 0, j = (n + 1) / 2; j < n; ++i, ++j) {
while (j < n && nums[i] * 2 > nums[j]) {
++j;
}
if (j < n) {
ans += 2;
}
}
return ans;
}
};

• class Solution:
def maxNumOfMarkedIndices(self, nums: List[int]) -> int:
nums.sort()
n = len(nums)
i, j = 0, (n + 1) // 2
ans = 0
while j < n:
while j < n and nums[i] * 2 > nums[j]:
j += 1
if j < n:
ans += 2
i, j = i + 1, j + 1
return ans


• func maxNumOfMarkedIndices(nums []int) (ans int) {
sort.Ints(nums)
n := len(nums)
for i, j := 0, (n+1)/2; j < n; i, j = i+1, j+1 {
for j < n && nums[i]*2 > nums[j] {
j++
}
if j < n {
ans += 2
}
}
return
}

• function maxNumOfMarkedIndices(nums: number[]): number {
nums.sort((a, b) => a - b);
const n = nums.length;
let ans = 0;
for (let i = 0, j = Math.floor((n + 1) / 2); j < n; ++i, ++j) {
while (j < n && nums[i] * 2 > nums[j]) {
++j;
}
if (j < n) {
ans += 2;
}
}
return ans;
}