Submission #526305

#	Time	Username	Problem	Language	Result	Execution time	Memory
526305		wai_hoang_0912	Cities (BOI16_cities)	C++17	100 / 100	2028 ms	45620 KiB

cities

#include <bits/stdc++.h>

using namespace std;

#define FORU(i, a, b) for(__typeof(b) i = a; i <= b; i ++)
#define FORD(i, b, a) for(__typeof(b) i = b; i >= a; i --)
#define UFOR(i, a, b) for(__typeof(b) i = a; i < b; i ++)
#define DFOR(i, b, a) for(__typeof(b) i = b; i > a; i --)
#define N 100005
#define oo 1000000000000000
#define pb push_back
#define fi first
#define se second
#define ll long long

typedef pair < ll, int > ii;
int n, k, m, s[8];
ll f[1 << 8][N];
vector < ii > a[N];

void read()
{
    cin >> n >> k >> m;
    FORU(i, 1, k)
        cin >> s[i];
    int u, v;
    ll c;
    FORU(i, 1, m)
    {
        cin >> u >> v >> c;
        a[u].pb(ii(c, v));
        a[v].pb(ii(c, u));
    }
}

void Dijkstra(int mask)
{
    priority_queue < ii, vector < ii >, greater < ii > > q;
    FORU(i, 1, n)
        if(f[mask][i] != oo)
            q.push(ii(f[mask][i], i));
    while(!q.empty())
    {
        int u = q.top().se;
        ll du = q.top().fi;
        q.pop();
        if(du != f[mask][u])
            continue;
        UFOR(i, 0, a[u].size())
        {
            int v = a[u][i].se;
            ll uv = a[u][i].fi;
            if(f[mask][v] > f[mask][u] + uv)
            {
                f[mask][v] = f[mask][u] + uv;
                q.push(ii(f[mask][v], v));
            }
        }
    }
}

void solve()
{
    FORU(i, 0, 1 << k)
        FORU(j, 1, n)
            f[i][j] = oo;
    FORU(i, 1, k)
        f[1 << (i - 1)][s[i]] = 0;
    UFOR(x, 1, 1 << k)
    {
        UFOR(y, 0, x)
        {
            if((x | y) != x)
                continue;
            int z = x ^ y;
            if(y > z)
                continue;
            FORU(i, 1, n)
                f[x][i] = min(f[x][i], f[y][i] + f[z][i]);
        }
        Dijkstra(x);
    }
    ll res = oo;
    FORU(i, 1, n)
        res = min(res, f[(1 << k) - 1][i]);
    if(res == oo)
        cout << -1;
    else
        cout << res;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    read();
    solve();
    return 0;
}

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