题目描述

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

思路

求解所有串的最长公共后缀。
由于是求解后缀，因此先将串逆序，然后一边输入一边两两比较。将公共部分存至ans中，最后再将串逆序输出。

代码

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;
int main() {
    int n;
    scanf("%d\n", &n);
    string s, ans;
    for (int i = 0; i < n; i++) {
        int j = 0, k = 0;
        getline(cin, s);
        reverse(s.begin(), s.end());
        if (i == 0) {
            ans = s;
            continue;
        }
        else {
            while (j < s.length() && k < ans.length() && s[j] == ans[k]) {
                j++;
                k++;
            }
            ans = s.substr(0, j);
        }
    }
    reverse(ans.begin(), ans.end());
    if (ans.size() == 0) ans = "nai";
    cout << ans;
    return 0;
}