LeetCode：Interleaving String

二维dp

dp[i][j] 表示是否能有s1[0...i-1]和[s2[0....j-1]组成s3【0.....i+j-1】

class Solution {public:    bool isInterleave(string s1, string s2, string s3) {        // Start typing your C/C++ solution below        // DO NOT write int main() function                 int len1 = s1.length();     int len2 = s2.length();     int len3 = s3.length();     if(len1+len2!=len3)        return false;     if(len1==0&&s2!=s3)        return false;     if(len2==0&&s1!=s3)        return false;    bool** dp = new bool *[len1+1];    for(int i =0;i<=len1;i++)        dp[i] = new bool[len2+1];    dp[0][0] = 1;    for(int i =1;i<=len1;i++)        if(dp[i-1][0]&&s1[i-1]==s3[i-1])           dp[i][0] = true;        else           dp[i][0] = false;    for(int i =1;i<=len2;i++)       if(dp[0][i-1]&&s2[i-1]==s3[i-1])           dp[0][i] = true;        else           dp[0][i] = false;    for(int i =1;i<=len1;i++)        for(int j = 1;j<=len2;j++)             if(dp[i-1][j]&&s1[i-1] == s3[i+j-1])                 dp[i][j] =1;            else if(dp[i][j-1]&&s2[j-1] == s3[i+j-1])                 dp[i][j] =1;            else            dp[i][j]=0;                 return dp[len1][len2];                 }};