Add 635_Design_Log_Storage_System.java

Author: Sean Prashad

Design/635_Design_Log_Storage_System.java

@@ -0,0 +1,40 @@
+class LogSystem {
+    private Map<String, Integer> delimiterMap;
+    private TreeMap<String, List<Integer>> logs;
+
+    public LogSystem() {
+        delimiterMap = new HashMap<>();
+        logs = new TreeMap<>();
+
+        delimiterMap.put("Year", 4);
+        delimiterMap.put("Month", 7);
+        delimiterMap.put("Day", 10);
+        delimiterMap.put("Hour", 13);
+        delimiterMap.put("Minute", 16);
+        delimiterMap.put("Second", 19);
+    }
+
+    public void put(int id, String timestamp) {
+        logs.putIfAbsent(timestamp, new ArrayList<>());
+        logs.get(timestamp).add(id);
+    }
+
+    public List<Integer> retrieve(String start, String end, String granularity) {
+        List<Integer> result = new ArrayList<>();
+
+        int idx = delimiterMap.get(granularity);
+
+        String searchStart = start.substring(0, idx);
+        String searchEnd = end.substring(0, idx);
+
+        for (String timestamp : logs.keySet()) {
+            String tSubstring = timestamp.substring(0, idx);
+
+            if (tSubstring.compareTo(searchStart) >= 0 && tSubstring.compareTo(searchEnd) <= 0) {
+                result.addAll(logs.get(timestamp));
+            }
+        }
+
+        return result;
+    }
+}