97. Interleaving String

题目原网址为https://leetcode.com/problems/interleaving-string/description/

一、题目

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.

For example,

Given:
s1 = 

"aabcc"

,
s2 = 

"dbbca"

,

When s3 = 

"aadbbcbcac"

, return true.

When s3 = 

"aadbbbaccc"

, return false.
二、代码
class Solution {
public:
bool isInterleave(string s1, string s2, string s3) {
int len1 = s1.size();
int len2 = s2.size();
if (len1 + len2 != s3.size())
return false;
vector<vector<bool>> dp(len1 + 1);
for (int i = 0; i <= len1; i++)
dp[i].resize(len2 + 1);
for (int i = 0; i <= len1; i++) {
for (int j = 0; j <= len2; j++) {
if (i == 0 && j == 0)
dp[i][j] = true;
else if (i == 0)
dp[i][j] = dp[i][j - 1] && s2[j - 1] == s3[i + j - 1];
else if (j == 0)
dp[i][j] = dp[i - 1][j] && s1[i - 1] == s3[i + j - 1];
else
dp[i][j] = dp[i][j - 1] && s2[j - 1] == s3[i + j - 1] || dp[i - 1][j] && s1[i - 1] == s3[i + j - 1];
}
}
return dp[len1][len2];
}
};