微软校招2015 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

43abc4aaab6abccde3abb

样例输出

YESNOYES
NO

#include <stdio.h>#include <stdlib.h>bool IsBeautiful(char *str, int length) {if(str == NULL || length < 3)return false;char c[3];int count[3] = {0, 0, 0};int i  = 0;for(int j = 0; j < 2; j++){if(i >= length)return false;c[j] = str[i];while(i < length && str[i] == c[j]){count[j]++;i++;}}for( ;i < length;) {c[2] = str[i];count[2] = 0;while(i < length && str[i] == c[2]) {count[2]++;i++;}if(c[0]+1 == c[1] && c[1]+1 == c[2] && count[0] >= count[1] && count[2] >= count[1]) {return true;}c[0] = c[1];c[1] = c[2];count[0] = count[1]; count[1] = count[2];}return false;}char buffer[10000005];int main(void) {int tests;int length;//freopen("beautiful_string.txt", "r", stdin);scanf("%d", &tests);while (tests--) {scanf("%d", &length);getchar();gets(buffer);if(IsBeautiful(buffer, length)) {printf("YES\n");}else {printf("NO\n");}}   return 0;}