97. Interleaving String

class Solution {
public boolean isInterleave(String s1, String s2, String s3) {
if(s1.length()+s2.length()!=s3.length())
return false;
boolean [][] dp=new boolean[s1.length()+1][s3.length()+1];
dp[0][0]=true;
for(int i=0;i<=s1.length();i++)
for(int j=i;j<=s3.length();j++)
{
if(i>0&&s1.charAt(i-1)==s3.charAt(j-1))
dp[i][j]=dp[i-1][j-1];
int k=j-i;
if(k<=s2.length()&&k>0&&s2.charAt(k-1)==s3.charAt(j-1))
dp[i][j]=dp[i][j]||dp[i][j-1];
}
return dp[s1.length()][s3.length()];
}
}