# Buddy Strings in Python

Suppose we have two strings A and B of lowercase letters; we have to check whether we can swap two letters in A so that the result equals to B or not.

So, if the input is like A = "ba", B = "ab", then the output will be True.

To solve this, we will follow these steps −

• if size of A is not same as size of B, then
• return False
• otherwise when A and B has any element that are not common, then
• return False
• otherwise when A is same as B and all characters are distinct in A, then
• return False
• otherwise,
• count:= 0
• for i in range 0 to size of A, do
• if A[i] is not same as B[i], then
• count := count + 1
• if count is same as 3, then
• return False
• return True

Let us see the following implementation to get better understanding −

## Example

Live Demo

class Solution:
def buddyStrings(self, A, B):
if len(A)!=len(B):
return False
elif sorted(A)!=sorted(B):
return False
elif A==B and len(set(A))==len(A):
return False
else:
count=0
for i in range(len(A)):
if A[i]!=B[i]:
count+=1
if count==3:
return False
return True
ob = Solution()
print(ob.buddyStrings("ba","ab"))

## Input

"ba","ab"

## Output

True

Updated on: 04-Jul-2020

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