Split Two Strings to Make Palindrome — LeetCode 1616 Python Solution

The problem

You are given two strings a and b of the same length. Choose an index and split both strings at the same index, splitting a into two strings: aprefix and asuffix where a = aprefix + asuffix, and splitting b into two strings: bprefix and bsuffix where b = bprefix + bsuffix.

Example

Input

a = "x", b = "y"

Output

true

Python solution

class Solution:
    def checkPalindromeFormation(self, a: str, b: str) -> bool:
        def check1(a: str, b: str) -> bool:
            i, j = 0, len(b) - 1
            while i < j and a[i] == b[j]:
                i, j = i + 1, j - 1
            return i >= j or check2(a, i, j) or check2(b, i, j)

        def check2(a: str, i: int, j: int) -> bool:
            return a[i : j + 1] == a[i : j + 1][::-1]

        return check1(a, b) or check1(b, a)

Complexity

Pattern: Two Pointers

Use the order already in the input to discard half the search space at every step. LeetCode 1616. Split Two Strings to Make Palindrome is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Two Pointers.

The two pointers guide has the Python template for the pattern and the 201 LeetCode problems that use it.

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