#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;
#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif
#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second
const int SIZE = 1e6 + 5;
int n, mxdeg;
vector<int> adj[SIZE];
struct DS {
int p, cnt[5], mxD;
int cycle, csum;
int to[SIZE], sz[SIZE], sum[SIZE], deg[SIZE], mxdeg[SIZE];
void init() {
memset(cnt, 0, sizeof(cnt));
mxD = cycle = csum = 0;
cnt[0] = n - (p != 0);
iota(to + 1, to + n + 1, 1);
fill(sz + 1, sz + n + 1, 1);
fill(sum + 1, sum + n + 1, 0);
fill(deg + 1, deg + n + 1, 0);
fill(mxdeg + 1, mxdeg + n + 1, 0);
}
void build(int P = 0) {
p = P;
init();
FOR (i, 1, n) for (int j : adj[i]) if (i < j) Merge(i, j);
}
int dsu(int x) {
return x == to[x] ? x : (to[x] = dsu(to[x]));
}
void add(int x) {
cnt[mxdeg[x] < 4 ? mxdeg[x] : 4]++;
if (mxdeg[x] == 2 && sum[x] == 2 * sz[x]) cycle++, csum = sz[x];
mxD = max(mxD, mxdeg[x]);
}
void del(int x) {
cnt[mxdeg[x] < 4 ? mxdeg[x] : 4]--;
if (mxdeg[x] == 2 && sum[x] == 2 * sz[x]) cycle--;
}
void Merge(int a, int b) {
if (a == p || b == p) return;
int da = dsu(a), db = dsu(b);
if (da == db) del(da);
else del(da), del(db);
sum[da]++, sum[db]++;
mxdeg[da] = max(mxdeg[da], ++deg[a]);
mxdeg[db] = max(mxdeg[db], ++deg[b]);
if (da == db) {add(da);return;}
if (sz[da] < sz[db]) swap(da, db);
to[db] = da;
sz[da] += sz[db];
sum[da] += sum[db];
mxdeg[da] = max(mxdeg[da], mxdeg[db]);
add(da);
}
} ori, ds[4];
void Init(int N) {
n = N;
ori.build();
}
void Link(int a, int b) {
a++, b++;
if (a > b) swap(a, b);
adj[a].pb(b);
adj[b].pb(a);
ori.Merge(a, b);
int cur = ori.mxD;
if (cur == mxdeg + 1) {
if (cur == 4) {
FOR (i, 1, n) if (adj[i].size() == 4) {
ds[0].build(i);
break;
}
}
if (cur == 3) {
FOR (i, 1, n) if (adj[i].size() == 3) {
ds[0].build(i);
int k = 0;
for (int j : adj[i]) ds[++k].build(j);
break;
}
}
}
mxdeg = cur;
if (mxdeg == 4) ds[0].Merge(a, b);
else if (mxdeg == 3) FOR (i, 0, 3) ds[i].Merge(a, b);
}
int CountCritical() {
if (mxdeg <= 1) return n;
if (mxdeg == 2) return ori.cycle == 0 ? n : ori.cycle == 1 ? ori.csum : 0;
int ans = 0;
FOR (i, 0, (mxdeg == 3 ? 3 : 0)) ans += ds[i].mxD <= 1 || (ds[i].mxD == 2 && ds[i].cycle == 0);
return ans;
}
Compilation message
rings.cpp:68:2: error: extended character is not valid in an identifier
68 | if (da == db) {add(da);return;}
| ^
rings.cpp:68:5: error: extended character is not valid in an identifier
68 | if (da == db) {add(da);return;}
| ^
rings.cpp:68:8: error: extended character is not valid in an identifier
68 | if (da == db) {add(da);return;}
| ^
rings.cpp:68:11: error: extended character is not valid in an identifier
68 | if (da == db) {add(da);return;}
| ^
rings.cpp:69:2: error: extended character is not valid in an identifier
69 | if (sz[da] < sz[db]) swap(da, db);
| ^
rings.cpp:69:5: error: extended character is not valid in an identifier
69 | if (sz[da] < sz[db]) swap(da, db);
| ^
rings.cpp:69:8: error: extended character is not valid in an identifier
69 | if (sz[da] < sz[db]) swap(da, db);
| ^
rings.cpp:69:11: error: extended character is not valid in an identifier
69 | if (sz[da] < sz[db]) swap(da, db);
| ^
rings.cpp: In member function 'void DS::Merge(int, int)':
rings.cpp:68:2: error: '\U000000a0' was not declared in this scope
68 | if (da == db) {add(da);return;}
| ^
rings.cpp:69:4: error: expected ';' before '\U000000a0'
69 | if (sz[da] < sz[db]) swap(da, db);
| ^~
| ;
