Update array-sum.py

Miscellaneous/largest_contiguous_array_sum.py

@@ -21,3 +21,31 @@ def maxSumSubarray(a, n):
 
 a = list(map(int, input("Enter the array: ").split()))
 maxSumSubarray(a, len(a))
+
+# Python program for reversal algorithm of array rotation 
+
+# Function to reverse arr[] from index start to end 
+def rverseArray(arr, start, end): 
+    while (start < end): 
+        temp = arr[start] 
+        arr[start] = arr[end] 
+        arr[end] = temp 
+        start += 1
+        end = end-1
+
+# Function to left rotate arr[] of size n by d 
+def leftRotate(arr, d): 
+    n = len(arr) 
+    rverseArray(arr, 0, d-1) 
+    rverseArray(arr, d, n-1) 
+    rverseArray(arr, 0, n-1) 
+
+# Function to print an array 
+def printArray(arr): 
+    for i in range(0, len(arr)): 
+        print arr[i], 
+
+# Driver function to test above functions 
+arr = [1, 2, 3, 4, 5, 6, 7] 
+leftRotate(arr, 2) # Rotate array by 2 
+printArray(arr)