#97

Interleaving String

medium· 2-D DPruns: 0

Given strings s1, s2, and s3, find whether s3 is formed by an interleaving of s1 and s2. An interleaving is formed by splitting each string into non-empty substrings and concatenating the pieces in an alternating order, while preserving the relative order of characters within each original string.

wpm 0acc 100%time 0:000 / 572

class Solution:
    def isInterleave(self, s1: str, s2: str, s3: str) -> bool:
        if len(s1) + len(s2) != len(s3):
            return False
        m, n = len(s1), len(s2)
        dp = [[False] * (n + 1) for _ in range(m + 1)]
        dp[0][0] = True
        for i in range(m + 1):
            for j in range(n + 1):
                if i > 0 and s1[i - 1] == s3[i + j - 1]:
                    dp[i][j] = dp[i][j] or dp[i - 1][j]
                if j > 0 and s2[j - 1] == s3[i + j - 1]:
                    dp[i][j] = dp[i][j] or dp[i][j - 1]
        return dp[m][n]

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