ms在线笔试题

题目1 : Beautiful String

时间限制: 10000ms

单点时限: 1000ms

内存限制: 256MB

描述

We say a string is beautiful if it has the equal amount of 3 or more continuous letters (in increasing order.)

Here are some example of valid beautiful strings: "abc", "cde", "aabbcc", "aaabbbccc".

Here are some example of invalid beautiful strings: "abd", "cba", "aabbc", "zab".

Given a string of alphabets containing only lowercase alphabets (a-z), output "YES" if the string contains a beautiful sub-string, otherwise output "NO".

输入

The first line contains an integer number between 1 and 10, indicating how many test cases are followed.

For each test case: First line is the number of letters in the string; Second line is the string. String length is less than 10MB.

输出

For each test case, output a single line "YES"/"NO" to tell if the string contains a beautiful sub-string.

提示

Huge input. Slow IO method such as Scanner in Java may get TLE.

样例输入

4
3
abc
4
aaab
6
abccde
3
abb

样例输出

YES
NO
YES

NO

#include 
#include 
using namespace std;

int main(){
	int n;
	long long k;
	string s;
	cin >> n;
	while(n--){
		cin >> k >> s;
		for(int i = 0; i < k; ++i){
			if(i == k -1){
				cout << "NO" << endl;
				break;
			}
			int count = 1;
			bool flag = true;
			for(int j = i + 1; j < k; ++j){
				if(s[j] == s[i])
					count++;
				else
					break;
			}
			if(k < i + 3*count){
				continue;
			}
			for(int p = i + count; p <= i+2*count-1; ++p){
				if(s[p] != s[i] + 1){
					flag = false;
					break;
				}
			}
			if(!flag)
				continue;
			for(int q = i+2*count; q <= i + 3*count -1; ++q){
				if(s[q] != s[i] + 2){
					flag = false;
					break;
				}
			}
			if(flag){
				cout << "YES" << endl;
				break;
			}
			else{
				continue;
			}
		}
	}
	return 0;
}