PAT甲级A1077 Kuchiguse （20 分）

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

题意：给出n个字符串，让你找出这n个字符串的最长公共后缀并输出，如果没有输出“nai”。

思路：首先求出这些字符串的最小长度minLen，然后把所有字符串倒置，变成求所有字符串的最长公共前缀，再然后，开始逐个字符串匹配最大长度，找最长公共前缀。

参考代码： 

#include<cstdio>
#include<cstring>
#include<string>
#include<iostream>
#include<vector>
using namespace std;
int main()
{
	int n,minLen=260;
	scanf("%d\n",&n);
	vector<string> v;
	string s;
	for(int i=0;i<n;i++){
		getline(cin,s);
		reverse(s.begin(),s.end());
		if(s.size()<minLen) minLen=s.size();
		v.push_back(s);
	}
	for(int i=minLen;i>0;i--){
		bool flag=true;
		string str=v[0].substr(0,i);
		for(int j=1;j<n&&flag;j++){
			if(v[j].find(str)==-1){
				flag=false;
				break;
			}
		}
		if(flag) {
			reverse(str.begin(),str.end());
			cout<<str<<endl;
			return 0;
		}
	}
	cout<<"nai"<<endl;
	return 0;
}