Codeforces Round #719 (Div. 3)A. Do Not Be Distracted!
给一个string, 问是不是有重复出现过的不连续的char.
用set直接解决即可.
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#include "bits/stdc++.h" using namespace std; // fast read const auto fr = [](){ std::ios_base::sync_with_stdio(0); std::cin.tie(0); std::cout << std::fixed << std::setprecision(12); return 1; }(); template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v); template<typename A, typename B> ostream& operator<<(ostream &cout, pair<A, B> const &p) { return cout << "(" << p.first << ", " << p.second << ")"; }; template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v) { cout << "["; for(int i = 0; i < v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << "]"; } template<typename A, typename B> istream& operator>>(istream& cin, pair<A, B> &p) { cin >> p.first; return cin >> p.second; } // vars using ll = long long; using ull = unsigned long long; using ld = long double; using vi = std::vector<int>; using vl = std::vector<ll>; using vvi = std::vector<vi>; using vvl = std::vector<vl>; using pii = std::pair<int,int>; using pil = std::pair<int,ll>; using pli = std::pair<ll,int>; using pll = std::pair<ll,ll>; using vpii = std::vector<pii>; using vvpii = std::vector<vpii>; // consts ll M = 0; // ksm (kuai su mi) ll ksm(ll a,ll p){ll res=1;while(p){if(p&1){res=res*a%M;}a=a*a%M;p>>=1;}return res;} int main() { fr; int T; cin >> T; while (T --) { int N; cin >> N; int check[26] = {}; string s; cin >> s; int flag = 0; for (int i = 0; i < N; i++) { if(check[s[i] - 'A'] && i > 0 && s[i - 1] != s[i]) { flag++; break; } check[s[i] - 'A']++; } if(flag) { cout << "NO" << endl; } else { cout << "YES" << endl; } } return 0; } |