Find if a string starts and ends with another given string

Given a string str and a corner string cs, we need to find out whether the string str starts and ends with the corner string cs or not.
Examples: 

Input : str = "geeksmanishgeeks", cs = "geeks"
Output : Yes

Input : str = "shreya dhatwalia", cs = "abc"
Output : No

Algorithm 

• Find length of given string str as well as corner string cs. Let this length be n and cl respectively.
• If cl>n, return false as cs can't be greater than str.
• Otherwise, find the prefix and suffix of length cl from str. If both prefix and suffix match with corner string cs, return true otherwise return false.

Implementation:

Yes

Time Complexity: O(n)
Auxiliary Space: O(1)