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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 ping
s 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 toping
. - Each test case will call
ping
with strictly increasing values oft
. - Each call to ping will have
1 <= t <= 10^9
.
思路:就是一个queue,注意pop出来之后要check是否为空;
class RecentCounter {
LinkedList<Integer> queue;
public RecentCounter() {
this.queue = new LinkedList<Integer>();
}
public int ping(int t) {
if(queue.size() == 0) {
queue.add(t);
return queue.size();
} else if(t - queue.peek() <= 3000) {
queue.add(t);
return queue.size();
} else {
// pop until number < 3000;
while(!queue.isEmpty() && (t - queue.peek() > 3000)) {
queue.pop();
}
queue.add(t);
return queue.size();
}
}
}
/**
* Your RecentCounter object will be instantiated and called as such:
* RecentCounter obj = new RecentCounter();
* int param_1 = obj.ping(t);
*/