Example 1:
Input: s1 = "aabcc", s2 = "dbbca", s3 = "aadbbcbcac" Output: true
Example 2:
Input: s1 = "aabcc", s2 = "dbbca", s3 = "aadbbbaccc" Output: false
class Solution {
public:bool isInterleave(string s1, string s2, string s3) {
int n1=s1.size();
int n2=s2.size();
int n3=s3.size();
if((n1+n2)!=n3){
return false;
}
vector<vector<bool> > dp(n1+1,vector<bool>(n2+1,false));
// dp[i][j] 以 s1 i 和 s2 j 结尾 能否等于 s[i+j-1]
for(int i=0;i<=n1;++i){
for(int j=0;j<=n2;++j){
if(i==0&&j==0){
dp[i][j]=1;
}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[n1][n2];
}
};