Submission #715331

#	Time	Username	Problem	Language	Result	Execution time	Memory
715331		lam	Highway Tolls (IOI18_highway)	C++14	100 / 100	252 ms	16320 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 2e5 + 10;
typedef pair<int,int> ii;
#define ff first
#define ss second
int n,m;
ll dist,w1,w2,dist2;
vector <ii> adj[maxn];
ii e[maxn];
int d[maxn]; ii par[maxn];
int side[maxn], idx;
int dnc()
{
    int l=0; int r=m-1;
    while (l<r)
    {
        int mid=(l+r)/2;
        vector <int> dau(m,0);
        for (int i=0; i<=mid; i++) dau[i] = 1;
        ll temp = ask(dau);
        if (temp > dist) r = mid;
        else l=mid+1;
    }
    return r;
}
int trace(int id1, int id2, vector <int> nodes, vector <int> nodes2)
{
    int l=0; int r=nodes.size()-1;
    while (l<r)
    {
        int mid = (l+r+1)/2;
        vector <int> dau(m,1);
        dau[idx] = 0;
        for (int i=0; i<mid; i++) if (par[nodes[i]].ff!=-1) dau[par[nodes[i]].ss] = 0;
        for (int i:nodes2) if (par[i].ff!=-1) dau[par[i].ss]=0;
        if (ask(dau)>dist) l=mid;
        else r=mid-1;
    }
    return nodes[l];
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
  m=U.size(); n=N; w1=A; w2=B;
  fill_n(side,n,0);
  for (int i=0; i<n; i++) par[i]={-1,-1};
  cerr<<":>"<<endl;
  for (int i=0; i<n; i++) adj[i].clear();
  for (int i=0; i<m; i++) e[i].ff=U[i], e[i].ss = V[i], adj[e[i].ff].push_back({e[i].ss,i}), adj[e[i].ss].push_back({e[i].ff,i});
  vector <int32_t> dau(m,0);
  dist=ask(dau);
   cerr<<dist<<endl;
  idx = dnc();
  cerr<<idx<<endl;
  fill_n(d,n,-1);
  int u=e[idx].ff; int v=e[idx].ss;
  d[u]=d[v]=0; par[u] = par[v] = {-1,-1};
  dau[idx] = -1;
  queue<int> q;
  q.push(u); q.push(v);
  side[u] = 1; side[v] = 2;
  vector <int> nodes[3];
  nodes[1].push_back(u);
  nodes[2].push_back(v);
  while (!q.empty())
  {
      int u=q.front(); q.pop();
      for (ii i:adj[u])
      {
          int v=i.ff; int id = i.ss;
          if (d[v]==-1)
          {
              par[v] = {u,id};
              side[v] = side[u];
              d[v] = d[u]+1;
//              cerr<<u<<" - "<<v<<endl;
              dau[id] = side[v];
              nodes[side[v]].push_back(v);
              q.push(v);
          }
      }
  }
  answer(trace(1,2,nodes[1],nodes[2]), trace(2,1,nodes[2],nodes[1]));
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 31 / 31