Create LeetCode_362_Hit_Counter_Medium.ts

anxious-coder-lhs · web-flow · commit fc3614ac5480 · 2020-10-07T12:36:10.000+05:30
diff --git a/level_medium/LeetCode_362_Hit_Counter_Medium.ts b/level_medium/LeetCode_362_Hit_Counter_Medium.ts
@@ -0,0 +1,47 @@
+/**
+ * Probleml: Design a hit counter that keeps track of the total number of hits in the last 5 minutes.
+ * Solution: Uses a bounded buffer of exactly 300 seconds to keep track of the number of hits in that particular second. Each second bucket
+ * will keep track of the hits incurred in that particular second. Along with that, it will also keep track of the timestamp associated 
+ * with each bucket. This is required so that, when we round over and use the same buckets, we can correlate which time we are looking at
+ * with respect to a bucket.
+ */
+class HitCounter {
+    
+    hits: number[]
+    times: number[]
+    
+    constructor() {
+        this.hits = Array(300).fill(0)
+        this.times = Array(300).fill(0);
+    }
+
+    hit(timestamp: number): void {
+        const pos = timestamp % 300;
+        if (this.times[pos] !== timestamp) {
+            // Starting over, the last logged timestamp was before 5 mts.
+            this.hits[pos] = 1
+            this.times[pos] = timestamp
+        } else {
+            this.hits[pos]++
+        }
+    }
+
+    getHits(timestamp: number): number {
+        let count = 0
+        for (let idx = 0; idx < 300; idx++) {
+            if (timestamp - this.times[idx] < 300) {
+                // This existing time tick hit value is obselete and should not be added.
+                count += this.hits[idx]
+            }
+        }
+        
+        return count;
+    }
+}
+
+/**
+ * Your HitCounter object will be instantiated and called as such:
+ * var obj = new HitCounter()
+ * obj.hit(timestamp)
+ * var param_2 = obj.getHits(timestamp)
+ */
