[LeetCode] Interleaving String（dp）

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.

分析：非常好的DP的训练题，用dp矩阵存储的元素（i，j）表示s1中前i个元素，s2中前j个元素与s3中前i+j个元素相匹配

class Solution {
public:
    bool isInterleave(string s1, string s2, string s3) {
        int len1 = s1.size(),len2 = s2.size(),len3 = s3.size();
        if(len1+len2 != len3)
            return false;
        vector<bool> temp(len2+1,false);
        vector<vector<bool> > dp(len1+1,temp);//（i，j）表示s1中前i个元素，s2中前j个元素与s3中前i+j个元素相匹配

        for(int i=0;i<=len1;i++){
            for(int j=0;j<=len2;j++){
                if(i==0 && j==0){
                   dp[i][j]=true;
                   continue;
                }
                if(i>0 && s1[i-1]==s3[i+j-1] && dp[i-1][j]==true)
                    dp[i][j]=true;
                if(j>0 && s2[j-1]==s3[i+j-1] && dp[i][j-1]==true)
                    dp[i][j]=true;
            
            
            }//end for
        
        }//end for

       return dp[len1][len2];
    
    }
};