bestcoder3(1003)hdu4909(状态压缩+乱搞)

String

Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 524288/524288 K (Java/Others)
Total Submission(s): 443    Accepted Submission(s): 113

Problem Description

You hava a non-empty string which consists of lowercase English letters and may contain at most one '?'. Let's choose non-empty substring G from S (it can be G = S). A substring of a string is a continuous subsequence of the string. if G contains '?' then '?' can be deleted or replaced by one of lowercase english letters. After that if each letter occurs even number of times in G then G is a good substring. Find number of all good substrings.

 

Input

The input consists of an integer T, followed by T lines, each containing a non-empty string. The length of the string doesn't exceed 20000.

[Technical Specification]
1 <= T <= 100

 

Output

For each test case, print a single integer which is the number of good substrings of a given string.

 

Sample Input

    
    
    
    

     
     
     
     3
abc?ca
aabbcc
aaaaa
    
    
    
    

 

Sample Output

    
    
    
    

     
     
     
     7
6
6

     
     
     
     
 
      
 
       Hint 
      
 Good substrings of "abc?ca": "?", "c?", "?c", "c?c", "bc?c", "c?ca", "abc?ca" 
     
    
    
    
    

题意：就是给一个字符串，该字符串最多含一个问号，然后问你有多少个满足条件的子串，满足条件定义为，该子串里面的所有字符都出现偶数次，如果含有问号，可以将问号替换为任意字符也可以不替换（如果不替换，问号就算作空字符）

思路：由于只有26个小写字母，可以用26位的二进制来压缩子串的状态，那么首先对整个字符串处理，for一遍以后，每个位置都有一个对应的值（将该位置的字符异或到对应的位置上），如果有两个位置对应的值相同，那么这两个位置之间的子串就是满足条件的，可以分两种情况

1.不含问号，那么去掉问号处理一遍即可

2.含问号，那么可以枚举问号为26个字符，再分别处理每一次的情况即可

这题有点卡时，当时被坑了好久~