PAT (Advanced Level) Practice 1077 Kuchiguse (20 分)_综合

PAT (Advanced Level) Practice 1077 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

思路

找到最长的公共后缀
reverse之后找最长公共前缀
先求第一个字符串和第二个字符串的公共后缀, 再用这个后缀和第三个字符串求公共后缀… 直到和最后一个字符串求完公共后缀

AC code

#include<iostream>
#include<string>
#include<algorithm>
using namespace std;int main(){
    int N;string ans;cin>> N;getchar();  //接收换行符getline(cin,ans);reverse(ans.begin(),ans.end());for(int i=1;i<N;i++){
    string s;getline(cin,s);reverse(s.begin(),s.end());int len = min(s.length(),ans.length());for(int j=0;j<len;j++){
    if(ans[j]!=s[j]){
    ans = ans.substr(0,j); break;}}}if(ans.empty()){
    cout<<"nai";}else{
    reverse(ans.begin(),ans.end());cout<<ans;}return 0;
}