Submission #340840

#	Time	Username	Problem	Language	Result	Execution time	Memory
340840		ivan_tudor	Evacuation plan (IZhO18_plan)	C++14	100 / 100	1377 ms	45044 KiB

plan

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
struct edge{
  int x, c;
};
vector<edge> gr[N];
struct dst{
  int d, id;
};
int dist[N];
dst ord[N];
bool mark[N];
bool cmpdist(dst a, dst b){
  return a.d > b.d;
}

int par[N];
vector<int> arb[N];
int findt(int nod){
  if(nod == par[nod])
    return nod;
  par[nod] = findt(par[nod]);
  return par[nod];
}
void join(int son,int dad){
  son = findt(son);
  if(son != dad){
    par[son] = dad;
    arb[son].push_back(dad);
    arb[dad].push_back(son);
  }
}
int pr[20][N];
int in[N], out[N];
int cnt = 0;
void dfs_arb(int nod,int dad){
  pr[0][nod] = dad;
  in[nod] = ++cnt;
  for(auto x:arb[nod]){
    if(x!=dad){
      dfs_arb(x, nod);
    }
  }
  out[nod] = cnt;
}
bool isdad(int dad, int son){
  return in[dad] <= in[son] && out[son] <= out[dad];
}



int main()
{
  int n, m;
  cin>>n>>m;
  for(int i=1;i<=m;i++){
    int a, b, c;
    cin>>a>>b>>c;
    gr[a].push_back({b, c});
    gr[b].push_back({a, c});
  }
  for(int i=1;i<=n;i++){
    dist[i] = INT_MAX;
  }
  priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
  int k;
  cin>>k;
  for(int i=1;i<=k;i++){
    int o;
    cin>>o;

    dist[o] = 0;
    pq.push({0, o});
  }
  while(pq.size()){
    auto top = pq.top();
    pq.pop();
    int nod = top.second;
    int cost = top.first;
    if(cost == dist[nod]){
      for(auto e:gr[nod]){
        if(cost + e.c < dist[e.x]){
          dist[e.x] = cost + e.c;
          pq.push({dist[e.x], e.x});
        }
      }
    }
  }
  for(int i=1;i<=n;i++){
    ord[i] = {dist[i], i};
    par[i] = i;
  }
  sort(ord + 1, ord + n + 1, cmpdist);
  int root = 0;
  for(int i=1; i<=n;i++){
    int nod = ord[i].id;
    mark[nod] = true;
    root = nod;
    for(auto x:gr[nod]){
      int vec = x.x;
      if(mark[vec] == true){
        join(vec, nod); // il pun pe nod tata la vec;

      }
    }
  }
  dfs_arb(root, 0);
  for(int log =1; log < 17;log++){
    for(int nod = 1; nod<=n;nod++){
      pr[log][nod] = pr[log-1][pr[log-1][nod]];
    }
  }
  int q;
  cin>>q;
  for(int i =1 ; i<=q;i++){
    int a, b;
    cin>>a>>b;
    for(int p2 = 16;p2>=0;p2--){
      if(pr[p2][a] != 0 && isdad(pr[p2][a], b)== false){
        a = pr[p2][a];
      }
    }
    if(isdad(a, b) == false){
      a = pr[0][a];

    }
    cout<<dist[a]<<"\n";
  }
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46