Submission #1279743

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279743		longdeptrai	Cities (BOI16_cities)	C++20	74 / 100	6095 ms	96144 KiB

cities

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define LongDepTrai "cities"
#define ll long long
#define int long long
#define ull unsigned long long
#define ld long double
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define pll pair<ll,ll>
#define vi vector<int>
#define vii vector<ii>
#define vll vector<ll>
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) int((x).size())
#define order_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>

inline ll add(ll a, ll b, ll mod){ a += b; if(a >= mod) a -= mod; return a; }
inline ll sub(ll a, ll b, ll mod){ a -= b; if(a < 0) a += mod; return a; }
inline ll mul(ll a, ll b, ll mod){ return ( (ll)a * b ) % mod; }

static mt19937_64 rng((unsigned)chrono::steady_clock::now().time_since_epoch().count());
const int N=2e5+9;
const int INF=1e18;
int n,k,m,imp[N],d[2009][2009];
vii g[N];
void dijk(int u){
    for(int i=1;i<=n;i++){
        d[u][i]=INF;
    }
    d[u][u]=0;
    priority_queue<ii,vector<ii>,greater<ii>> q;
    q.push({d[u][u],u});

    while(q.size()){
        int z=q.top().se;
        int cost=q.top().fi;
        q.pop();
        if(cost!=d[u][z]) continue;
        for(ii x:g[z]){
            int v=x.fi;
            int w=x.se;

            if(d[u][v]>cost+w){
                d[u][v]=cost+w;
                q.push({d[u][v],v});
            }
        }
    }
}
int ans=INF;
void Try(int i,int sumu,int sumv,int u,int v){
    if(i>4){
        ans=min(ans,sumu+sumv);
        return;
    }
    Try(i+1,sumu+d[u][imp[i]],sumv,u,v);
    Try(i+1,sumu,sumv+d[v][imp[i]],u,v);
}
void sub4(){
    for(int i=1;i<=n;i++){
        dijk(i);
    }
    int res=INF;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            ans=INF;
            Try(1,0,0,i,j);
          //  cout<<i<<" "<<j<<" "<<ans<<"\n";
            res=min(res,ans+d[i][j]);
        }
    }
    cout<<res;
}
int f[N][(1<<5)];

void subac(){
    memset(f,0x3f,sizeof(f));
    priority_queue<ii,vector<ii>,greater<ii>> q;
    for(int i=0;i<k;i++){
        f[imp[i+1]][(1<<i)]=0;
    }
    for(int mask=0;mask<(1<<k);mask++){
        for(int i=1;i<=n;i++){
            for(int mask1=0;mask1<(1<<5);mask1++) {
                for(int mask2=0;mask2<(1<<5);mask2++){
                    if((mask1|mask2)==mask && (mask1&mask2)==0){
                        f[i][mask]=min(f[i][mask],f[i][mask1]+f[i][mask2]);
                        q.push({f[i][mask],i});
                    }
                }
            }
        }
        while(q.size()){
                int z=q.top().se;
                int cost=q.top().fi;
                q.pop();

                if(f[z][mask]!=cost) continue;
                for(ii x:g[z]){
                    int v=x.fi;
                    int w=x.se;

                    if(f[v][mask]>cost+w){
                        f[v][mask]=cost+w;
                        q.push({f[v][mask],v});
                    }
                }
            }
    }
    int res=INF;
    for(int i=1;i<=n;i++){
        res=min(res,f[i][(1<<k)-1]);
    }
    cout<<res;
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);

    if(fopen(LongDepTrai".inp","r")){
        freopen(LongDepTrai".inp","r",stdin);
        freopen(LongDepTrai".out","w",stdout);
    }

    cin>>n>>k>>m;
    for(int i=1;i<=k;i++){
        cin>>imp[i];
    }

    for(int i=1;i<=m;i++){
        int u,v,c;
        cin>>u>>v>>c;
        g[u].pb({v,c});
        g[v].pb({u,c});
    }
    /*if(k==4){
        sub4();
    }
    else{*/
        subac();
    //}





    return 0;
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:129:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |         freopen(LongDepTrai".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cities.cpp:130:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  130 |         freopen(LongDepTrai".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 0 / 26