Algorithm
Problem Name: 933. Number of Recent Calls
You have a RecentCounter class which counts the number of recent requests within a certain time frame.
Implement the RecentCounter class:
RecentCounter()Initializes the counter with zero recent requests.int ping(int t)Adds a new request at timet, wheretrepresents some time in milliseconds, and returns the number of requests that has happened in the past3000milliseconds (including the new request). Specifically, return the number of requests that have happened in the inclusive range[t - 3000, t].
It is guaranteed that every call to ping uses a strictly larger value of t than the previous call.
Example 1:
Input ["RecentCounter", "ping", "ping", "ping", "ping"] [[], [1], [100], [3001], [3002]] Output [null, 1, 2, 3, 3] Explanation RecentCounter recentCounter = new RecentCounter(); recentCounter.ping(1); // requests = [1], range is [-2999,1], return 1 recentCounter.ping(100); // requests = [1, 100], range is [-2900,100], return 2 recentCounter.ping(3001); // requests = [1, 100, 3001], range is [1,3001], return 3 recentCounter.ping(3002); // requests = [1, 100, 3001, 3002], range is [2,3002], return 3
Constraints:
1 <= t <= 109- Each test case will call
pingwith strictly increasing values oft. - At most
104calls will be made toping.
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
class RecentCounter {
public:
RecentCounter() {
}
int ping(int t) {
while (!q.empty() && t - q.front() > 3000) {
q.pop_front();
}
q.push_back(t);
return q.size();
}
private:
deque < int>q;
};
Input
Output
#2 Code Example with Java Programming
Code -
Java Programming
class RecentCounter {
private Queue queue;
public RecentCounter() {
queue = new LinkedList < >();
}
public int ping(int t) {
while (!queue.isEmpty() && t - queue.peek() > 3000) {
queue.remove();
}
queue.add(t);
return queue.size();
}
}
Input
Output
#3 Code Example with Javascript Programming
Code -
Javascript Programming
const RecentCounter = function() {
this.pings = [];
};
RecentCounter.prototype.ping = function(t) {
if (t === null) return null;
if (t > 3000) {
let delta = t - 3000;
while (this.pings.length > 0 && this.pings[0] < delta) {
this.pings.shift();
}
}
this.pings.push(t);
return this.pings.length;
};
Input
Output
#4 Code Example with Python Programming
Code -
Python Programming
class RecentCounter:
def __init__(self):
self.p = collections.deque()
def ping(self, t):
self.p.append(t)
while self.p[0] < t - 3000:
self.p.popleft()
return len(self.p)
Input
Output
#5 Code Example with C# Programming
Code -
C# Programming
using System.Collections.Generic;
namespace LeetCode
{
public class _0933_NumberOfRecentCalls
{
private readonly Queue < int> queue;
public _0933_NumberOfRecentCalls()
{
queue = new Queue<int>();
}
public int Ping(int t)
{
queue.Enqueue(t);
while (t - queue.Peek() > 3000)
queue.Dequeue();
return queue.Count;
}
}
}
Input
Output