首页 > 代码库 > zoj 3818 Pretty Poem(暴力处理字符串)2014年牡丹江赛区网络赛
zoj 3818 Pretty Poem(暴力处理字符串)2014年牡丹江赛区网络赛
Poetry is a form of literature that uses aesthetic and rhythmic qualities of language. There are many famous poets in the contemporary era. It is said that a few ACM-ICPC contestants can even write poetic code. Some poems has a strict rhyme scheme like "ABABA" or "ABABCAB". For example, "niconiconi" is composed of a rhyme scheme "ABABA" with A = "ni" and B = "co".
More technically, we call a poem pretty if it can be decomposed into one of the following rhyme scheme: "ABABA" or "ABABCAB". The symbol A, B and C are different continuous non-empty substrings of the poem. By the way, punctuation characters should be ignored when considering the rhyme scheme.
You are given a line of poem, please determine whether it is pretty or not.
Input
There are multiple test cases. The first line of input contains an integer T indicating the number of test cases. For each test case:
There is a line of poem S (1 <= length(S) <= 50). S will only contains alphabet characters or punctuation characters.
Output
For each test case, output "Yes" if the poem is pretty, or "No" if not.
Sample Input
3 niconiconi~ pettan,pettan,tsurupettan wafuwafu
Sample Output
Yes Yes No
题意:给出一个长度不超过50的字符串,判断它是不是pretty串。pretty串的定义如下:如果一个串可以写成ABABA或者ABABCAB的形式,且A、B、C两两不相等,那么这个串就是pretty串。
分析:因为长度不超过50,所以可以直接枚举A、B的长度,然后暴力求解。比赛时我枚举的是AB整体的长度,不知道为什么一直WA。取子串时,可以用substr取代循环。
#include<iostream> #include<string> using namespace std; bool is_pretty1(string s) { if(s.length() < 5) return false; for(int lenA = 1; lenA <= (s.length() - 2) / 3; lenA++) { string A = s.substr(0, lenA); for(int lenB = 1; lenA * 3 + lenB * 2 <= s.length(); lenB++) { if(lenA * 3 + lenB * 2 != s.length()) continue; string B = s.substr(lenA, lenB); if(A != B) { string AA = s.substr(lenA + lenB, lenA); string BB = s.substr(lenA * 2 + lenB, lenB); string AAA = s.substr(lenA * 2 + lenB * 2, lenA); if(A == AA && A == AAA && B == BB) return true; } } } return false; } bool is_pretty2(string s) { if(s.length() < 7) return false; for(int lenA = 1; lenA <= (s.length() - 4) / 3; lenA++) { string A = s.substr(0, lenA); for(int lenB = 1; 3 * lenA + 3 * lenB < s.length(); lenB++) { string B = s.substr(lenA, lenB); if(A != B) { int lenC = s.length() - 3 * lenA - 3 * lenB; string AA = s.substr(lenA + lenB, lenA); string BB = s.substr(lenA * 2 + lenB, lenB); string C = s.substr(lenA * 2 + lenB * 2, lenC); string AAA = s.substr(lenA * 2 + lenB * 2 + lenC, lenA); string BBB = s.substr(lenA * 3 + lenB * 2 + lenC, lenB); if(A == AA && A == AAA && B == BB && B == BBB && A != C && B != C) return true; } } } return false; } bool is_pretty(string s) { return is_pretty1(s) || is_pretty2(s); } int main() { int T; string tmp; cin >> T; while(T--) { cin >> tmp; string s = ""; for(int i = 0; i < tmp.length(); i++) if(isalpha(tmp[i])) s += tmp[i]; if(is_pretty(s)) cout << "Yes" << endl; else cout << "No" << endl; } return 0; }
zoj 3818 Pretty Poem(暴力处理字符串)2014年牡丹江赛区网络赛