362. Design Hit Counter

Version #1 Circular Array

69.23 %
class HitCounter {
    int[] time;
    int[] count;
    /** Initialize your data structure here. */
    public HitCounter() {
        // time index = timestamp % 300, we can override the previous value since it has expired
        time = new int[300];
        count = new int[300];
    }
   
    /** Record a hit.
        @param timestamp - The current timestamp (in seconds granularity). */
    public void hit(int timestamp) {
        int index = timestamp % 300;
        if (time[index] != timestamp) {
            time[index] = timestamp;
            count[index] = 1;
        } else {
            count[index]++;
        }
    }
   
    /** Return the number of hits in the past 5 minutes.
        @param timestamp - The current timestamp (in seconds granularity). */
    public int getHits(int timestamp) {
        int result = 0;
        for (int i = 0; i < 300; i++) {
            if (time[i] + 300 > timestamp) {
                result += count[i];
            }
        }
        return result;
    }
}