Interleaving String

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.

• Time: O(n)
• Space: O(n)

public boolean isInterleave(String s1, String s2, String s3) {
    int len1 = s1.length(), len2 = s2.length(), len3 = s3.length();
    if (len1 + len2 != len3) {
        return false;
    }
    boolean[][] dp = new boolean[len1 + 1][len2 + 1];
    dp[0][0] = true;
    for (int i = 1; i <= len1; i++) {
        if (s3.charAt(i - 1) == s1.charAt(i - 1) && dp[i - 1][0])
            dp[i][0] = true;
    }
    for (int j = 1; j <= len2; j++) {
        if (s3.charAt(j - 1) == s2.charAt(j - 1) && dp[0][j - 1])
            dp[0][j] = true;
    }
    for (int i = 1; i <= len1; i++) {
        for (int j = 1; j <= len2; j++) {
            if (((s3.charAt(i + j - 1) == s1.charAt(i - 1) && dp[i - 1][j]))
             || ((s3.charAt(i + j - 1)) == s2.charAt(j - 1) && dp[i][j - 1]))
                dp[i][j] = true;
        }
    }
    return dp[len1][len2];
}