Submission #69496

#	Time	Username	Problem	Language	Result	Execution time	Memory
69496		funcsr	낙하산 고리들 (IOI12_rings)	C++17	55 / 100	4026 ms	105212 KiB

rings

#include <iostream>
#include <algorithm>
#include <vector>
#define rep(i, n) for (int i=0; i<(n); i++)
#define pb push_back
#define INF (1LL<<60)
#define all(x) (x).begin(), (x).end()
#define _1 first
#define _2 second
using namespace std;
typedef pair<int, int> P;

int N;
vector<int> G[1000000];

void Init(int N_) {
  N = N_;
}

void Link(int a, int b) {
  //cout<<a<<"<->"<<b<<"\n";
  G[a].pb(b);
  G[b].pb(a);
}

int ord[1000000], low[1000000];
bool used[1000000];
int R[1000000];

void dfs(int x, int p, int r) {
  used[x] = true;
  ord[x] = low[x] = r;
  if (p == -1) R[x] = -1;

  for (int t : G[x]) if (t != p) {
    if (used[t]) {
      low[x] = min(low[x], ord[t]);
      continue;
    }
    dfs(t, x, r+1);
    low[x] = min(low[x], low[t]);
    if (p == -1 || low[t] >= ord[x]) R[x]++;
  }
}

int CountCritical() {
  rep(i, N) used[i] = false, ord[i] = low[i] = -1, R[i] = 0;
  int r_def = 0;
  rep(i, N) if (!used[i]) dfs(i, -1, 0), r_def++;

  int deg0 = 0, deg1 = 0, deg3 = 0;
  auto add = [&](int d) {
    if      (d == 0) deg0++;
    else if (d == 1) deg1++;
    else if (d >= 3) deg3++;
  };
  auto rem = [&](int d) {
    if      (d == 0) deg0--;
    else if (d == 1) deg1--;
    else if (d >= 3) deg3--;
  };
  rep(i, N) add(G[i].size());

  int ctr = 0;
  rep(x, N) {
    rem(G[x].size());
    for (int t : G[x]) {
      rem(G[t].size());
      add(G[t].size()-1);
    }

    //if (deg3 == 0) cout<<"x="<<x<<": "<<r_def+R[x]<<" ::: deg1 should be 2*"<<(r_def+R[x]-deg0)<<" (deg1="<<deg1<<")\n";
    if (deg3 == 0 && 2*((r_def+R[x])-deg0) == deg1) ctr++;

    for (int t : G[x]) {
      rem(G[t].size()-1);
      add(G[t].size());
    }
    add(G[x].size());
  }
  return ctr;
}

• Subtask 1: 20 / 20
• Subtask 2: 17 / 17
• Subtask 3: 18 / 18
• Subtask 4: 0 / 14
• Subtask 5: 0 / 31