Count Subarray with k odds

import java.util.*;

class Solution {
    public int countSubarrays(int[] arr, int k) {
        LinkedList<Integer> lt = new LinkedList<>();
        int pr = -1, ans = 0, n = arr.length;
        for (int i = 0; i <= n; i++) {
            if (i == n || arr[i] % 2 == 1) {
                if (lt.size() == k) {
                    int f = lt.getFirst() - pr;
                    int s = i - lt.getLast();
                    ans += f * s;
                    pr = lt.removeFirst();
                }
                lt.add(i);
            }
        }
        
        return ans;
    }
}