public boolean isInterleave(String s1, String s2, String s3) {

if(s1.length() + s2.length() != s3.length())

return false;

int m = s1.length();

int n = s2.length();

boolean[][] isreach = new boolean[m + 1][n + 1];

for(int i = 0; i <= m; i++ ){

for(int j = 0; j <= n; j++){

if(i == 0 && j == 0)

isreach[i][j] = true;

else if(i == 0)

isreach[i][j] = isreach[i][j - 1] && (s2.charAt(j - 1) == s3.charAt(i + j - 1));

else if(j == 0)

isreach[i][j] = isreach[i - 1][j] && (s1.charAt(i - 1) == s3.charAt(i + j - 1));

else {

isreach[i][j] = (isreach[i][j - 1] && (s2.charAt(j - 1) == s3.charAt(i + j - 1))) || (isreach[i - 1][j] && (s1.charAt(i - 1) == s3.charAt(i + j - 1)));

}

}

}

return isreach[m][n];

}

public static void main(String[] args) {

InterleavingString test = new InterleavingString();

String s1 = "aabcc";

String s2 = "dbbca";

String s3 = "aadbbcbcac";

System.out.println(test.isInterleave(s1, s2, s3));

}