A.Competitive Problem Setting
题意:比较多个字符串的前三位,如果全部不同则输出Yes 否则为 No.
思路:截取前三位,放入set中进行比较即可
#include <bits/stdc++.h> typedef long long ll; const int maxn = 1e5+7; using namespace std; string s,s1; set<string>ss; int main(){ int T; cin>>T; while(T--){ int n; cin>>n; ss.clear(); int flag = 0; for(int i=0;i<n;i++){ cin>>s; s1 = s.substr(0,3); if(flag==0&&ss.count(s1)){ flag = 1; } else ss.insert(s1); } if(flag) cout<<"No"<<endl; else cout<<"Yes"<<endl; } return 0; }
B.Binary Matrix Transform