Submission #564031

#	Time	Username	Problem	Language	Result	Execution time	Memory
564031		perchuts	Cities (BOI16_cities)	C++17	100 / 100	1822 ms	44380 KiB

cities

#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define pb push_back
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ii = pair<int,int>;
using iii = tuple<int,int,int>;

const ll inf = 1e18;
const int mod = 1e9+7;
const int maxn = 1e5+100;

template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }

int a[5],n,k,m;

vector<pair<ll,int>>g[maxn];
ll dist[1<<5][maxn];

priority_queue<pair<ll,int>, vector<pair<ll,int>>, greater<pair<ll,int>>>pq;

void dijkstra(ll d[maxn]){
    for(int i=1;i<=n;++i)pq.push({d[i],i});
    while(!pq.empty()){
        pair<ll,int> me = pq.top();pq.pop();
        int u = me.second;
        if(me.first>d[u])continue;
        for(pair<ll,int>e :g[u]){
            if(d[e.second]>e.first+me.first){
                d[e.second] = e.first + me.first;
                pq.push({d[e.second],e.second});
            }
        }
    }
}

int main(){_
    cin>>n>>k>>m;

    for(int i=0;i<k;++i){
        memset(dist[1<<i], 0x3F, 8*(n+1));
        cin>>a[i], dist[1<<i][a[i]] = 0;
    }

    for(int i=1;i<=m;++i){
        ll c;int u,v;cin>>u>>v>>c;
        g[u].pb({c,v});
        g[v].pb({c,u});
    }

    for(int i=1;i<(1<<k);++i){
        if(__builtin_popcount(i)>1){
            memset(dist[i], 0x3F, 8*(n+10));
            for(int j=0;j<k;++j)
                if(i>>j&1)
                    for(int l=1;l<=n;++l)
                        ckmin(dist[i][l],dist[i^1<<j][l]+dist[1<<j][l]);
        }
        dijkstra(dist[i]);
    }

    ll ans = inf;

    for(int i=1;i<=n;++i)ckmin(ans,dist[(1<<k)-1][i]);

    cout<<ans;
}

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