Description

Write a method anagram(s,t) to decide if two strings are anagrams or not.

Clarification

What is Anagram?

• Two strings are anagram if they can be the same after change the order of characters.

Example

Given s = "abcd", t = "dcab", return true.
Given s = "ab", t = "ab"

Challenge

O(n) time, O(1) extra space

解題：題目給定兩個字符串，判斷這兩個字符串除了字符字符順序不同外，是否相等。最容易想到的還是將字符排序，判斷對位字符是否相等。不過在java中，要對字符串中的字符排序，只能轉化成字符數組，那麽就不滿足challenge條件了。但是用其他方法（例如哈希表），代碼就只能處理字母或者ASCII中的字符，有損通用性，沒什麽意思。貼一下排序方法的代碼：

 1 public class Solution {
 
 2     /**
 3      * @param s: The first string
 4      * @param t: The second string
 5      * @return: true or false
 6      */
 7     public boolean anagram(String s, String t) {
 8         // write your code here
 9         char[]arr_s = s.toCharArray();
10         char[]arr_t = t.toCharArray();
11         Arrays.sort(arr_s);
 
12         Arrays.sort(arr_t);
13         return String.valueOf(arr_s).equals(String.valueOf(arr_t));
14     }
15 }

158. Valid Anagram【LintCode by java】