YE DAWG

your_return_calculator.rb

@@ -2,14 +2,27 @@
 
 class YourReturnCalculator < ReturnCalculator
   def calculate!
-    # Write your code here.
-    # You have access to the `snapshots` variable.
-    #
-    # You can access the following properties of a snapshot:
-    # snapshot.date
-    # snapshot.cash_flow
-    # snapshot.market_value
-
-    BigDecimal.new(0)
+    $length = snapshots.length
+    $i = 0
+    subperiods = Array.new
+    while $i < $length - 1 do
+        market_value_1 = snapshots[$i].market_value
+        market_value_2 = snapshots[$i+1].market_value
+        cash_flow_2 = snapshots[$i+1].cash_flow
+        if market_value_1 == 0
+            return 0
+        end
+        subperiod = ((market_value_2 - cash_flow_2)/market_value_1) - 1
+        subperiods.push(subperiod)
+        $i += 1
+    end
+    # geo linking time
+    answer = 1
+    $i = 0
+    while $i < $length - 1 do
+        answer *= (1 + subperiods[$i])
+        $i += 1
+    end
+    BigDecimal.new(answer - 1)
   end
 end