牛客网 PAT（甲级） 1012 Kuchiguse (20)

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?

输入描述:

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.

输出描述:

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".

输入例子:

3
Itai nyan~
Ninjin wa iyadanyan~
uhhh nyan~

这道题坑爹的就在于，是不是真的看懂了题目。我第一次，很费劲的读了好几遍，没太看懂，好像是说日本话会在句尾加一个缀词，显示人物性格。但是这和题目有什么关系呢？后来再百度翻译也没看懂，猜想应该是字符串之间的比较吧，就想到了strcmp()，但是其实这道题和这个没太大关系。参考了大神们的博客，终于理解了一下意思，总之归位两种情况：
输出为"nai"的时候，是在n行输入的字符里，只要有一行最后的字符串（倒着数，不管多长，只要大于等于1），和其他所有行的，结尾，都没有公共字符串（必须严格从最后一个字符开始倒着数），即没有任何吻合的情况，就直接nai了，全部结束。

不然，我们就输出所有行（严格按照顺序，倒着数），大家公共的部分，即大家都有的部分。
#include<iostream>
#include<string>


using namespace std;


int main() {
	
	string kuru;
	string s;
	int n;
	cin >> n;
	getchar();
	getline(cin, kuru);
	//getchar();
	for (int i = 1; i < n; i++) {
		int j = 0;
		getline(cin, s);
		while (kuru[kuru.size() - j - 1] == s[s.size() - j - 1]) {
			j++;


			if (j == s.size() || j == kuru.size()) {
				break;
			}
		}


		if (j == 0) {
			cout << "nai" << endl;
			return 0;
		}


		string ss;
		ss.assign(kuru, kuru.size() - j, j);
		kuru = ss;
	}
	cout << kuru << endl;
	return 0;
}