Add T1.java

Author: seanprashad

Miscellaneous/T1.java

@@ -0,0 +1,70 @@
+import java.util.*;
+
+public class T1 {
+    // Epoch timestamp with list of users who had an action for the respective
+    // timestamp
+    private TreeMap<Integer, Set<Integer>> logs;
+
+    public T1() {
+        logs = new TreeMap<>();
+    }
+
+    public void put(int id, int timestamp) {
+        logs.putIfAbsent(timestamp, new HashSet<>());
+        logs.get(timestamp).add(id);
+    }
+
+    public List<Integer> retrieve(int totalMinutes, int intervalLength) {
+        List<Integer> result = new ArrayList<>();
+
+        int intervalStart = 0, intervalEnd = intervalStart + intervalLength;
+
+        while (intervalStart <= totalMinutes) {
+            int end = Math.min(totalMinutes, intervalEnd + 1);
+            SortedMap<Integer, Set<Integer>> submap = logs.subMap(intervalStart, end);
+            result.add(submap.size());
+
+            intervalStart += intervalLength;
+            intervalEnd += intervalLength;
+        }
+
+        return result;
+    }
+
+    public static void main(String[] args) {
+        /*
+         * [1, 1518290973]
+         * [1, 1518291096]
+         * [1, 1518291200]
+         * [1, 1518291200]
+         * [2, 1518291032]
+         * [3, 1518291095]
+         * [3, 1518291178]
+         * [4, 1518291120]
+         * 
+         * 1 -> 3 minutes in total
+         * 2 -> 1 minutes in total
+         * 3 -> 2 minutes in total
+         * 4 -> 1 minutes in total
+         * 
+         * 2 users spend 0-1 minutes in total - users 2 and 4
+         * 2 users spend 2-3 minutes in total - users 1 and 3
+         */
+        int[][] logs = new int[][] { { 1, 1518290973 }, { 2, 1518291032 }, { 3, 1518291095 }, { 1, 1518291096 },
+                { 4, 1518291120 }, { 3, 1518291178 }, { 1, 1518291200 }, { 1, 1518291200 } };
+
+        T1 logRetrieval = new T1();
+
+        for (int[] log : logs) {
+            logRetrieval.put(log[0], log[1]);
+        }
+
+        for (int interval : logRetrieval.retrieve(1, 2)) {
+            System.out.print(interval + ", ");
+        }
+
+        System.out.println();
+
+        return;
+    }
+}