A1077. Kuchiguse

The Japanese language is notorious for its sentence ending particles. Personal preference of such particles can be considered as a reflection of the speaker's personality. Such a preference is called "Kuchiguse" and is often exaggerated artistically in Anime and Manga. For example, the artificial sentence ending particle "nyan~" is often used as a stereotype for characters with a cat-like personality:

• Itai nyan~ (It hurts, nyan~)
• Ninjin wa iyada nyan~ (I hate carrots, nyan~)

Now given a few lines spoken by the same character, can you find her Kuchiguse?

Input Specification:

Each input file contains one test case. For each case, the first line is an integer N (2<=N<=100). Following are N file lines of 0~256 (inclusive) characters in length, each representing a character's spoken line. The spoken lines are case sensitive.

Output Specification:

For each test case, print in one line the kuchiguse of the character, i.e., the longest common suffix of all N lines. If there is no such suffix, write "nai".

Sample Input 1:

3
Itai nyan~
Ninjin wa iyadanyan~
uhhh nyan~

Sample Output 1:

nyan~

Sample Input 2:

3
Itai!
Ninjinnwaiyada T_T
T_T

Sample Output 2:

nai

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 #include<string.h>
 using namespace std;
 void rev(char a[]){
     int len = strlen(a);
     for(int i = ; i < len / ; i++)
         swap(a[i],a[len -  - i]);
 }
 int main(){
     int N, minL = , tag = , len = ;
     char str[][], sen[];
     scanf("%d", &N);
     getchar();
     for(int i = ; i < N; i++){
         gets(str[i]);
         rev(str[i]);
         if(minL > strlen(str[i]))
             minL = strlen(str[i]);
     }
     for(int i = ; i < minL; i++){
         char c = str[][i];
         for(int j = ; j < N; j++)
             if(str[j][i] != c){
                 tag = ;
                 break;
             }
         if(tag == )
             break;
         len++;
     }
     if(len != )
         for(int j = len - ; j >= ; j--)
             printf("%c", str[][j]);
     else
         printf("nai");
     cin >> N;
     return ;
 }

总结：

1、本题即求公共后缀，由于每个字符串长度不一，可以在输入字符串后逆序，转换为求公共前缀。

2、关于字符串的处理，本题无法使用scanf的%s读入字符串，因为字符串中存在空格。所以可以用gets()，在遇到回车时结束。但要注意，在scanf读入N后，还存在一个回车键，需要被吸收掉，否则会导致gets()读到一个回车空串。

3、由于PAT不支持gets()读入带空格的一行。以后遇到复杂的字符串题时，使用string而不是char[]。