First_Negative_in_window.java

public static void main(String[] args) {
        FastReader s = new FastReader();
        int n = s.nextInt();
        int k = s.nextInt();
        int a[] = new int[n];
        for (int i = 0; i < n; i++)
            a[i] = s.nextInt(); //accepting array

        Queue<Integer> q = new LinkedList<>();
        for (int i = 0; i < k; i++) {
            if (a[i] < 0)
                q.offer(i); // Adding the index of -ve element
        } // Running this loop till the size of window
        for (int i = k; i < n; i++) {
            if (!q.isEmpty())
                System.out.print(a[q.peek()] + " "); // if q is not empty display the -ve term
            else
                System.out.print(0 + " ");

            while (!q.isEmpty() && q.peek() < i - k + 1) { // Out from window range
                q.poll();
            }

            if (a[i] < 0)
                q.offer(i);
        }

        if (!q.isEmpty())
            System.out.print(a[q.peek()] + " ");
        else
            System.out.print(0 + " ");
        System.out.println();
    }