# Wrapper over the recursive function leftRotateRec()
# It left rotates arr by d.
def leftRotate(arr, d, n):
leftRotateRec(arr, 0, d, n);
def leftRotateRec(arr, i, d, n):
'''
* Return If number of elements to be
rotated is zero or equal to array size
'''
if (d == 0 or d == n):
return;
'''
* If number of elements to be rotated
is exactly half of array size
'''
if (n - d == d):
swap(arr, i, n - d + i, d);
return;
''' If A is shorter '''
if (d < n - d):
swap(arr, i, n - d + i, d);
leftRotateRec(arr, i, d, n - d);
''' If B is shorter '''
else:
swap(arr, i, d, n - d);
''' This is tricky '''
leftRotateRec(arr, n - d + i, 2 * d - n, d);
''' UTILITY FUNCTIONS '''
''' function to print an array '''
def printArray(arr, size):
for i in range(size):
print(arr[i], end = " ");
print();
'''
* This function swaps d elements starting at
* index fi with d elements starting at index si
'''
def swap(arr, fi, si, d):
for i in range(d):
temp = arr[fi + i];
arr[fi + i] = arr[si + i];
arr[si + i] = temp;
# Driver Code
if __name__ == '__main__':
arr = [1, 2, 3, 4, 5, 6, 7];
leftRotate(arr, 2, 7);
printArray(arr, 7);
# This code is contributed by Rohit_ranjan