Submission #1059757

#	Time	Username	Problem	Language	Result	Execution time	Memory
1059757		vjudge1	Cities (BOI16_cities)	C++17	100 / 100	5904 ms	169788 KiB

cities

#include<bits/stdc++.h>

using namespace std;
const int M=1e5+10;
int n,m,k;
long long  f[M][1<<5];
vector<pair<int,int>> ke[M];
priority_queue<tuple<long long ,int ,int >,vector<tuple<long long ,int ,int > > ,greater<tuple<long long ,int ,int > > > h;
long long  tmp[1<<5];
vector<int> submask[1<<5];
void dij()
{
  while(!h.empty())
  {
    auto [val,mask,u]=h.top();h.pop();
    if(f[u][mask]<val) continue;
    for(pair<int,int> v:ke[u])
    {
      for(int i:submask[mask]) tmp[i]=min(f[v.first][i],val+f[v.first][i^mask]+v.second);
      for(int i:submask[mask])
      {
        if(tmp[i]<f[v.first][i])
        {
          f[v.first][i]=tmp[i];
          h.push({f[v.first][i],i,v.first});
          tmp[i]=1e18;
        }
      }
    }
  }
}
int32_t main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  #define task "1"
  if(fopen(task".inp","r"))
  {
    freopen(task".inp","r",stdin);
    freopen(task".out","w",stdout);
  }
  cin >> n >> k >> m;
  for(int i=0;i<(1<<k);i++)
  {
    for(int j=0;j<(1<<k);j++) if((i&j)==i) submask[i].push_back(j);
  }
  for(int i=1;i<=n;i++)
  {
    for(int j=1;j<(1<<k);j++) f[i][j]=1e18;
  }
  for(int i=0;i<(1<<k);i++) tmp[i]=1e18;
  for(int i=0;i<k;i++)
  {
    int x;
    cin >> x;
    h.push({0,1<<i,x});
    f[x][1<<i]=0;
  }
  for(int i=1;i<=m;i++)
  {
    int u,v;
    long long w;
    cin >> u >> v >> w;
    ke[u].push_back({v,w});
    ke[v].push_back({u,w});
  }
  dij();
  long long  kq=1e18;
  for(int i=1;i<=n;i++) kq=min(kq,f[i][(1<<k)-1]);
  cout << kq;
}

Compilation message (stderr)

cities.cpp: In function 'int32_t main()':
cities.cpp:40:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |     freopen(task".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
cities.cpp:41:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |     freopen(task".out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 26 / 26