Finding duplicate in an array

Author: AnushreeBagchi

duplicate_in_arr.py

@@ -0,0 +1,27 @@
+def test_case(testcase):
+    arr = testcase[0]
+    solution = testcase[1]
+    output = find_duplicate(arr)
+    if output == solution:
+        print("Pass")
+    else:
+        print("Fail")
+
+def find_duplicate(arr):
+    curr_sum = 0
+    expected_sum = 0
+    for num in arr:
+        curr_sum += num
+    for i in range(len(arr)-1):
+        expected_sum += i
+    return curr_sum - expected_sum
+
+input_arr = [0,1,2,1,3,4,5]
+out = 1
+testcase = [input_arr, out]
+test_case(testcase)
+
+input_arr = [0,1,2,3,3,4,5]
+out = 3
+testcase = [input_arr, out]
+test_case(testcase)