LeetCode Interleaving String

最新推荐文章于 2019-09-18 20:15:24 发布

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本文介绍了一种用于判断字符串s3是否由字符串s1和s2交错组成的算法。通过使用动态规划的方法，该算法能够有效地解决这一问题，并给出了具体的实现代码。

题目：

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.

class Solution {
public:
	bool isInterleave(string s1, string s2, string s3) {
		int n1 = s1.size(), n2 = s2.size(), n3 = s3.size();
		if (n1 + n2 != n3)
			return false;
		bool dp[1000][1000];
		dp[0][0] = true;
		for (int i = 1; i <= s1.size(); i++)
			dp[i][0] = dp[i - 1][0] && s1[i - 1] == s3[i - 1];
		for (int j = 1; j <= s2.size(); j++)
			dp[0][j] = dp[0][j - 1] && s2[j - 1] == s3[j - 1];
		for (int i = 1; i <= s1.size(); i++) {
			for (int j = 1; j <= s2.size(); j++)
				dp[i][j] = (dp[i - 1][j] && s1[i - 1] == s3[i + j - 1]) || (dp[i][j - 1] && s2[j - 1] == s3[i + j - 1]);

		}
		return dp[n1][n2];
	}
};