Submission #1045982

#	Time	Username	Problem	Language	Result	Execution time	Memory
1045982		mychecksedad	Bridges (APIO19_bridges)	C++17	100 / 100	931 ms	15832 KiB

bridges

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
#define ff first
#define ss second
const int N = 1e6+100, M = 1e5+10, K = 52, MX = 30;
 
 
struct Dsu {
  vector<int> s, p;
  vector<pair<int,int>> poop;
  int sz;
  Dsu(int n){
    sz = n;
    s.resize(n+1, 1);
    p.resize(n+1);
    for(int i = 0; i <= n; ++i) p[i] = i;
  }
  int find(int v){
    if(p[v] == v) return v;
    return find(p[v]);
  }
  void merge(int a, int b){
    a = find(a);
    b = find(b);
    
    if(a != b){
      if(s[a] > s[b]){
        swap(a, b);
      }
      s[b] += s[a];
      p[a] = b;
      poop.pb({a, b});      
    }else{
      poop.pb({-1, -1
  });
    }
  }
  void rollback(){
    if(poop.size() == 0) return;
    if(poop.back().ff == -1){
      poop.pop_back();
      return;
    }
    int a = poop.back().ff;
    int b = poop.back().ss;
    poop.pop_back();
    p[a] = a;
    s[b] -= s[a];
  }
};
 
 
int n, m, q, ans[N];
vector<array<int, 4>> edges;
array<int, 3> upd[N];
array<int, 4> qr[N];
set<array<int , 4>> SE;
int S = 1100;
void solve(){
  cin >> n >> m;
  for(int i = 0; i < m; ++i){
    int u, v, w; cin >> u >> v >> w;
    edges.pb({-w, v, u, i});
    SE.insert({-w, v, u, i});
  }
  // sort(all(edges), greater<array<int, 4>>());
  vector<int> pos(m);
  
  vector<int> used(m);
  cin >> q;
  int pu = 0;
  // vector<array<int, 3>> upd;
  // vector<array<int, 4>> qr;
  for(int y = 0; y < q; y += S){
    int k = min(q, y+S) - y;
    int qq = 0, u = 0;
    for(int j = 0; j < k; ++j){
      int t, uu, v; cin >> t >> uu >> v;
      if(t == 1){
        --uu;
        upd[u] = {v, uu, j};
        ++u;
      }else{
        qr[qq] = {v, uu, j, qq};
        ++qq;
      }
    }
 
    Dsu d(n);
 
    sort(qr, qr+qq, greater<array<int, 4>>());
    
 
    auto it = SE.begin();
    for(int l = 0; l < u; ++l) used[upd[l][1]] = 1;
 
 
    for(int j = 0; j < qq; ++j){
      int w = qr[j][0];
      // cout << w << " : q\n" ;
      while(it != SE.end() && -(*it)[0] >= w){
        if(used[(*it)[3]]) ++it;
        else{
          d.merge((*it)[1], (*it)[2]);
          // cout << edges[pu][3] << " : upd" << '\n';
          ++it;
        }
      }
 
      int roll = 0;
      for(int l = u - 1; l >= 0; --l){
        int idx = upd[l][1];
        if(used[idx] > 1) continue;
        if(upd[l][2] < qr[j][2]){
          used[idx] = l + 2;
        }
      }
      for(int l = 0; l < u; ++l){
        int idx = upd[l][1];
        if(!(used[idx] == 1 || used[idx] == l + 2)) continue;
        // used[idx] = 1;
        if(upd[l][2] < qr[j][2]){
          if(upd[l][0] >= w){
            ++roll;
            d.merge(edges[idx][1], edges[idx][2]);
          }
        }else{
          if(-edges[idx][0] >= w){
            ++roll;
            d.merge(edges[idx][1], edges[idx][2]);
          }
        }
      }
      for(int l = 0; l < u; ++l) used[upd[l][1]] = 1;
      // cout << qr[j][1] << ' ';
      ans[qr[j][3]] = d.s[d.find(qr[j][1])];
      for(int l = 0; l < roll; ++l){
        d.rollback();
      }
    }
    for(int l = 0; l < u; ++l){
      int idx = upd[l][1];
      used[idx] = 0;
      SE.erase(SE.find(edges[idx]));
      edges[idx][0] = -upd[l][0];
      SE.insert(edges[idx]);
    }
 
 
    for(int l = 0; l < qq; ++l) cout << ans[l] << '\n';
  
  }
}
 
 
int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  while(tt--){
    solve();
    en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

Compilation message (stderr)

bridges.cpp: In function 'void solve()':
bridges.cpp:78:7: warning: unused variable 'pu' [-Wunused-variable]
   78 |   int pu = 0;
      |       ^~
bridges.cpp: In function 'int main()':
bridges.cpp:165:15: warning: unused variable 'aa' [-Wunused-variable]
  165 |   int tt = 1, aa;
      |               ^~

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 27 / 27