added solution

HTN.java

@@ -0,0 +1,55 @@
+import java.io.*;
+import java.util.*;
+
+/* Run by entering file name, program will output answer
+ * atarw11@outlook.com (Atharva Washimkar)
+ * Time complexity: O (N)
+ */
+
+public class HTN {
+
+  public static void main (String [] t) throws IOException {
+    BufferedReader in = new BufferedReader (new InputStreamReader (System.in));
+    BufferedReader file = new BufferedReader (new FileReader (in.readLine()));
+
+    List <Snapshot> list = new ArrayList <Snapshot> ();
+    String ln;
+
+    while (true) {
+      ln = file.readLine ();
+
+      if (ln == null) {
+        break;
+      }
+
+      t = ln.split (",");
+      list.add (new Snapshot (Double.parseDouble (t [1]), Double.parseDouble (t [2])));
+    }
+
+    double current_market_value = 0.0, previous_market_value = 0.0;
+    List <Double> subperiods = new ArrayList <Double> ();
+
+    for (int s = 1; s < list.size (); s++) {
+      current_market_value = list.get (s).market_value - list.get (s - 1).cash_flow;
+      previous_market_value = list.get (s - 1).market_value;
+      subperiods.add (current_market_value / previous_market_value - 1);
+    }
+
+    double time_weighted_return = 1.0;
+
+    for (int s = 0; s < subperiods.size (); s++) {
+      time_weighted_return *= (1.0 + subperiods.get (s));
+    }
+
+    System.out.println ((time_weighted_return - 1) * 100);
+  }
+}
+
+class Snapshot {
+  double cash_flow, market_value;
+
+  public Snapshot (double cash_flow, double market_value) {
+    this.cash_flow = cash_flow;
+    this.market_value = market_value;
+  }
+}