[Codeforces] Round #736 (Div. 1) A. Web of Lies

Codeforces Round #736 (Div. 1) A. Web of Lies

  • Time : O(q)
  • Space : O(v + e)
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#include <bits/stdc++.h>

#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")//Comment optimisations for interactive problems (use endl)
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")

struct PairHash {inline std::size_t operator()(const std::pair<int,int> & v) const {return v.first*31+v.second;}};

#define MAX_N 202020
#define INF 987654321
#define EPS 1e-9
#define ll long long
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vall3 vector<array<ll,3>>
#define all3 array<ll,3>
#define all5 array<ll,5>
#define vall5 vector<all5>
#define vll vector<ll>
#define vs vector<string>
#define usll unordered_set<ll>
#define uspll unordered_set<pll, PairHash>
#define vvs vector<vs>
#define vvll vector<vll>
#define all(a) begin(a), end(a)

using namespace std;

usll f[MAX_N];
void conn(ll u, ll v, ll& res) {
if(f[min(u,v)].empty()) res--;
f[min(u,v)].insert(max(u,v));
}

void deconn(ll u, ll v, ll& res) {
f[min(u,v)].erase(max(u,v));
if(f[min(u,v)].empty()) res++;
}

int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
//cin>>tc;
for(ll i = 1; i <= tc; i++) {
ll n, m, q, u, v, t;
cin>>n>>m;
for(ll j = 0; j < m; j++) {
cin>>u>>v;
conn(u,v,n);
}
cin>>q;
for(ll j = 0; j < q; j++) {
cin>>t;
if(t == 1) {
cin>>u>>v;
conn(u,v,n);
} else if(t == 2) {
cin>>u>>v;
deconn(u,v,n);
} else {
cout<<n<<endl;
}
}
}
return 0;
}
Author: Song Hayoung
Link: https://songhayoung.github.io/2022/06/12/PS/Codeforces/div1-736-a/
Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 4.0 unless stating additionally.