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][s2.length()+1];

dp[0][0] = true;

for (int i = 0; i <= s1.length(); i++){

for (int j = 0; j <= s2.length(); j++){

boolean s1Check = false;

boolean s2Check = false;

if (i > 0) {

s1Check = dp[i-1][j] && s3.charAt(i+j-1) == s1.charAt(i-1);

}

if (j > 0) {

s2Check = dp[i][j-1] && s3.charAt(i+j-1) == s2.charAt(j-1);

}

if (i>0 || j>0) {

dp[i][j] = s1Check || s2Check;

}

}

}

return dp[s1.length()][s2.length()];

}