LeetCode(97) Interleaving String(动态规划)

题目描述

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.

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首先容易想到的是深度搜索（所谓一言不合，就搜索），但是容易超时哦。

public class Solution {
//dp[i][j]-->s[i+j+1];
public boolean search(String s1,int p1,String s2,int p2,String s3,int p3){
if(p3==s3.length()&&p1==s1.length()&&p2==s2.length()){
return true;
}
if(p1==s1.length()) return s3.substring(p3).equals(s2.substring(p2))?true:false;
if(p2==s2.length()) return s3.substring(p3).equals(s1.substring(p1))?true:false;
if(s1.charAt(p1)==s3.charAt(p3)&&s2.charAt(p2)==s3.charAt(p3)){
return search(s1,p1+1,s2,p2,s3,p3+1)||search(s1,p1,s2,p2+1,s3,p3+1);
}
if(s1.charAt(p1)==s3.charAt(p3)){
return search(s1,p1+1,s2,p2,s3,p3+1);
}
if(s2.charAt(p2)==s3.charAt(p3)){
return search(s1,p1,s2,p2+1,s3,p3+1);
}
return false;

}

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

return search(s1,0,s2,0,s3,0);
}
}

看看改进版本吧；