_933.java

package com.fishercoder.solutions;

import java.util.Deque;
import java.util.LinkedList;

/**
 * 933. Number of Recent Calls
 *
 * Write a class RecentCounter to count recent requests.
 * It has only one method: ping(int t), where t represents some time in milliseconds.
 * Return the number of pings that have been made from 3000 milliseconds ago until now.
 * Any ping with time in [t - 3000, t] will count, including the current ping.
 * It is guaranteed that every call to ping uses a strictly larger value of t than before.
 *
 * Example 1:
 * Input: inputs = ["RecentCounter","ping","ping","ping","ping"], inputs = [[],[1],[100],[3001],[3002]]
 * Output: [null,1,2,3,3]
 *
 * Note:
 * Each test case will have at most 10000 calls to ping.
 * Each test case will call ping with strictly increasing values of t.
 * Each call to ping will have 1 <= t <= 10^9.
 * */
public class _933 {
    public static class Solution1 {
        public static class RecentCounter {

            Deque<Integer> deque;

            public RecentCounter() {
                deque = new LinkedList<>();
            }

            public int ping(int t) {
                while (!deque.isEmpty() && t - deque.getFirst() > 3000) {
                    deque.removeFirst();
                }
                deque.addLast(t);
                return deque.size();
            }
        }
    }
}