题目地址

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 <iostream>
#include <vector>
#include<algorithm>
#include <cmath>
#include<map>
#include<cstring>
#include<queue>
#include<string>
#include<set>
#include<stack>
using namespace std;
typedef long long ll;
const int maxn=1010,inf=100000000;
int n;string s[maxn];
int main(){
    cin>>n;getchar();
    for(int i=0;i<n;i++) {
        getline(cin,s[i]);
        reverse(s[i].begin(),s[i].end());
    }
    int i=0,flag=0;
    for( i=0;i<s[0].length();i++){
        for(int j=1;j<n;j++){
            if(s[j][i]!=s[j-1][i]) {
                flag=1;    break;              //不能让flag等于下标，这样在首字符idx==0时flag=0；无法判别；
            }
        }
        if(flag) break;
    }
    if(i==0) {
        cout<<"nai"<<endl;
        return 0;
    }
    string ans=s[0].substr(0,i);
    reverse(ans.begin(),ans.end());
    cout<<ans;
}