Given s1, s2, s3, check if s3 is an interleaving of s1 and s2. Characters from s1 and s2 appear in s3 in their relative order.
2D DP: dp[i][j] = True if s3[:i+j] can be formed by interleaving s1[:i] and s2[:j].
💡 Pro tip: Understand this problem deeply — don't just memorize the code. Try explaining the approach out loud as if teaching a friend. If you can explain it simply, you truly understand it!
isInterleave('aabcc', 'dbbca', 'aadbbcbcac')
True