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[leecode]Scramble String

时间:2014-09-02 00:17:33      阅读:260      评论:0      收藏:0      [点我收藏+]

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Scramble String

Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.

Below is one possible representation of s1 = "great":

    great
   /      gr    eat
 / \    /  g   r  e   at
           /           a   t

To scramble the string, we may choose any non-leaf node and swap its two children.

For example, if we choose the node "gr" and swap its two children, it produces a scrambled string "rgeat".

    rgeat
   /      rg    eat
 / \    /  r   g  e   at
           /           a   t

We say that "rgeat" is a scrambled string of "great".

Similarly, if we continue to swap the children of nodes "eat" and "at", it produces a scrambled string "rgtae".

    rgtae
   /      rg    tae
 / \    /  r   g  ta  e
       /       t   a

We say that "rgtae" is a scrambled string of "great".

Given two strings s1 and s2 of the same length, determine if s2 is a scrambled string of s1.

算法思路:

分治法:其实就是暴力法= =///

代码如下:

 1 public class Solution {
 2     public boolean isScramble(String s1,String s2){
 3         if(s1.length() != s2.length()) return false;
 4         if(s1.length() <= 1 && s1.equals(s2)) return true;
 5         if(s1.length() == 2){
 6             if(s1.equals(s2) ) return true;
 7             if(s1.charAt(0) == s2.charAt(1) && s1.charAt(1) == s2.charAt(0)) return true;
 8             return false;
 9         }
10         char[] s1Array = s1.toCharArray();
11         char[] s2Array = s2.toCharArray();
12         Arrays.sort(s2Array);
13         Arrays.sort(s1Array);
14         for(int i = 0; i < s1.length(); i++){
15             if(s1Array[i] != s2Array[i])
16                 return false;
17         }
18         boolean result = false;
19         for(int i = 1; i < s1.length();i++){
20             String s1pre = s1.substring(0,i);
21             String s1suf = s1.substring(i);
22             String s2pre = s2.substring(0, i);
23             String s2suf = s2.substring(i);
24             result = isScramble(s1pre, s2pre) && isScramble(s1suf, s2suf);
25             if(!result){
26                 String s3pre = s2.substring(0, s1.length() - i);
27                 String s3suf = s2.substring(s1.length() - i);
28                 result = isScramble(s1pre, s3suf) && isScramble(s1suf, s3pre);
29             }
30             if(result) return true;
31         }
32         return result;
33     }
34     
35 }

 

[leecode]Scramble String

标签:des   style   blog   http   color   os   io   ar   for   

原文地址:http://www.cnblogs.com/huntfor/p/3950546.html

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