First Negative In Every Window

import java.util.*;
class Solution {
    public int[] first_negative_in_every_window(int[] nums, int k) {
        int n = nums.length;
        if (k <= 0 || k > n) return new int[0];
        Deque<Integer> q = new ArrayDeque<>();
        int[] ans = new int[n - k + 1];
        int t = 0;
        for (int i = 0; i < n; i++) {
            if (nums[i] < 0) q.offerLast(i);
            while (!q.isEmpty() && q.peekFirst() <= i - k) q.pollFirst();
            if (i >= k - 1) ans[t++] = q.isEmpty() ? 0 : nums[q.peekFirst()];
        }
        return ans;
    }
}

function first_negative_in_every_window(nums, k) {
    var n = nums.length;
    if (k <= 0 || k > n) return [];
    var q = [];
    var head = 0;
    var ans = [];
    for (var i = 0; i < n; i++) {
        if (nums[i] < 0) q.push(i);
        while (head < q.length && q[head] <= i - k) head++;
        if (i >= k - 1) ans.push(head < q.length ? nums[q[head]] : 0);
    }
    return ans;
}

<?php
function first_negative_in_every_window($nums, $k) {
    $n = count($nums);
    if ($k <= 0 || $k > $n) return [];
    $q = [];
    $head = 0;
    $ans = [];
    for ($i = 0; $i < $n; $i++) {
        if ($nums[$i] < 0) $q[] = $i;
        while ($head < count($q) && $q[$head] <= $i - $k) $head++;
        if ($i >= $k - 1) $ans[] = $head < count($q) ? $nums[$q[$head]] : 0;
    }
    return $ans;
}
?>

from typing import List

def first_negative_in_every_window(nums: List[int], k: int) -> List[int]:
    n = len(nums)
    if k <= 0 or k > n:
        return []
    q = []
    head = 0
    ans = []
    for i in range(n):
        if nums[i] < 0:
            q.append(i)
        while head < len(q) and q[head] <= i - k:
            head += 1
        if i >= k - 1:
            ans.append(nums[q[head]] if head < len(q) else 0)
    return ans

use std::collections::VecDeque;
fn first_negative_in_every_window(nums: Vec<i32>, k: i32) -> Vec<i32> {
    let n = nums.len();
    if k <= 0 { return vec![]; }
    let ku = k as usize;
    if ku > n { return vec![]; }
    let mut q: VecDeque<usize> = VecDeque::new();
    let mut ans: Vec<i32> = Vec::new();
    for i in 0..n {
        if nums[i] < 0 { q.push_back(i); }
        while let Some(&idx) = q.front() {
            if idx + ku <= i { q.pop_front(); } else { break; }
        }
        if i + 1 >= ku {
            if let Some(&idx) = q.front() { ans.push(nums[idx]); } else { ans.push(0); }
        }
    }
    ans
}

function first_negative_in_every_window(nums: number[], k: number): number[] {
    var n = nums.length;
    if (k <= 0 || k > n) return [];
    var q: number[] = [];
    var head = 0;
    var ans: number[] = [];
    for (var i = 0; i < n; i++) {
        if (nums[i] < 0) q.push(i);
        while (head < q.length && q[head] <= i - k) head++;
        if (i >= k - 1) ans.push(head < q.length ? nums[q[head]] : 0);
    }
    return ans;
}