Java for LeetCode 097 Interleaving String 【HARD】

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.

解题思路：

DP问题，JAVA实现如下：

	static public boolean isInterleave(String s1, String s2, String s3) {
		if (s1.length() + s2.length() != s3.length())
			return false;
		boolean[] dp = new boolean[s2.length() + 1];
		dp[0] = true;

		for (int j = 1; j <= s2.length(); j++)
			dp[j] = dp[j - 1] && s2.charAt(j - 1) == s3.charAt(j - 1);

		for (int i = 1; i <= s1.length(); i++) {
			dp[0] = dp[0] && s1.charAt(i - 1) == s3.charAt(i - 1);
			for (int j = 1; j <= s2.length(); ++j) {
				dp[j] = (dp[j] && s1.charAt(i - 1) == s3.charAt(i + j - 1))
						|| (dp[j - 1] && s2.charAt(j - 1) == s3.charAt(i + j
								- 1));
			}
		}
		return dp[s2.length()];
	}