/*
IN THE NAME OF GOD
*/
#include <bits/stdc++.h>
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef long double ld;
#define F first
#define S second
#define Mp make_pair
#define pb push_back
#define pf push_front
#define size(x) ((ll)x.size())
#define all(x) (x).begin(),(x).end()
#define kill(x) cout << x << '\n', exit(0);
#define fuck(x) cout << "(" << #x << " , " << x << ")" << endl
#define endl '\n'
const int N = 3e5+23, lg = 18;
ll Mod = 1e9+7; //998244353;
inline ll MOD(ll a, ll mod=Mod) {a%=mod; (a<0)&&(a+=mod); return a;}
inline ll poww(ll a, ll b, ll mod=Mod) {
ll ans = 1;
a=MOD(a, mod);
while (b) {
if (b & 1) ans = MOD(ans*a, mod);
b >>= 1;
a = MOD(a*a, mod);
}
return ans;
}
ll n, m, ans, sz[N], par[N];
set<pii> glob;
set<int> eout[N], ein[N], st[N];
int getPar(int v) {return (par[v]==0 ? v : par[v]=getPar(par[v]));}
void merge(int v, int u) {
v=getPar(v), u=getPar(u);
if(u == v) return;
if(sz[v] < sz[u]) swap(v,u);
ans += (sz[v]*size(st[u]) + sz[u]*size(st[v]));
// fuck(ans);
par[u] = v;
sz[v] += sz[u];
for(auto it : st[u]) {
if(st[v].find(it)!=st[v].end()) ans-=sz[v];
else st[v].insert(it);
}
eout[u].erase(v);
eout[v].erase(u);
ein[v].erase(u);
ein[u].erase(v);
for(auto it : eout[u]) {
ein[it].erase(u);
ein[it].insert(v);
eout[v].insert(it);
if(eout[it].find(v) != eout[it].end()) glob.insert({it,v});
}
for(auto it : ein[u]) {
eout[it].erase(u);
eout[it].insert(v);
ein[v].insert(it);
if(ein[it].find(v) != ein[it].end()) glob.insert({it,v});
}
}
int main () {
ios_base::sync_with_stdio(false), cin.tie(0);
cin>>n>>m;
fill(sz+1, sz+n+1, 1);
for(int i=1; i<=n; i++) st[i].insert(i);
for(int v,u,i=1; i<=m; i++) {
cin>>v>>u;
if(getPar(v)!=getPar(u) && st[pu].find(v)==st[pu].end()) {
int pv=getPar(v), pu=getPar(u);
eout[pv].insert(pu);
ein[pu].insert(pv);
st[pu].insert(v);
ans += sz[pu];
if(eout[pu].find(pv) != eout[pu].end()) {
glob.insert({v, u});
while(size(glob) > 0) {
pii tmp = *(glob.begin());
if(getPar(tmp.F)!=getPar(tmp.S))merge(getPar(tmp.F), getPar(tmp.S));
glob.erase(tmp);
}
}
}
cout<<ans<<endl;
// if(i == 8) {
// for(int j=1; j<=n; j++) fuck(getPar(j));
// }
}
return 0;
}
Compilation message
joitter2.cpp: In function 'int main()':
joitter2.cpp:88:39: error: 'pu' was not declared in this scope; did you mean 'u'?
88 | if(getPar(v)!=getPar(u) && st[pu].find(v)==st[pu].end()) {
| ^~
| u
joitter2.cpp:89:31: error: redeclaration of 'int pu'
89 | int pv=getPar(v), pu=getPar(u);
| ^~
joitter2.cpp:88:39: note: '<typeprefixerror>pu' previously declared here
88 | if(getPar(v)!=getPar(u) && st[pu].find(v)==st[pu].end()) {
| ^~
