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[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];        }};