Submission #467213

#	Time	Username	Problem	Language	Result	Execution time	Memory
467213		Killer2501	Cities (BOI16_cities)	C++14	100 / 100	3224 ms	76428 KiB

cities

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define task "262144"
#define pll pair<ll, ll>
#define pi pair<ll, pll>
#define fi first
#define se second

using namespace std;
const ll mod = 1e15;
const ll N = 2e5+5;
const int base = 313;
ll n, m, t, k, T, ans, tong, a[N], dp[N][(1<<6)];
vector<pll> adj[N];
vector<ll> kq;
ll pw(ll k, ll n)
{
    ll total = 1;
    for(; n; n >>= 1)
    {
        if(n & 1)total = total * k % mod;
        k = k * k % mod;
    }
    return total;
}
void sol()
{
    cin >> n >> k >> m;
    for(int i = 1; i <= k; i ++)
    {
        ll x;
        cin >> x;
        --x;
        kq.pb(x);
    }
    while(m -- > 0)
    {
        ll x, y, w;
        cin >> x >> y >> w;
        --x;
        --y;
        adj[x].pb({w, y});
        adj[y].pb({w, x});
    }
    for(int i = 0; i < n; i ++)for(int j = 1; j < (1<<k); j ++)dp[i][j] = mod;
    for(int i = 0; i < k; i ++)dp[kq[i]][(1<<i)] = 0;
    for(int mask = 0; mask < (1<<k); mask ++)
    {
        priority_queue< pll, vector<pll>, greater<pll> > pq;
        for(int i = 0; i < n; i ++)
        {
            for(int j = mask; j > 0; j = (j - 1) & mask)
            {
                dp[i][mask] = min(dp[i][mask], dp[i][j] + dp[i][mask^j]);
            }
            if(dp[i][mask] < mod)pq.push({dp[i][mask], i});
        }
        while(!pq.empty())
        {
            pll u = pq.top();
            pq.pop();
            if(u.fi != dp[u.se][mask])continue;
            //cout << u.se <<" "<<mask <<" "<<u.fi << '\n';
            if(mask == (1<<k)-1)
            {
                cout << u.fi;
                return;
            }
            for(pll v : adj[u.se])
            {
                if(dp[v.se][mask] > u.fi + v.fi)
                {
                    dp[v.se][mask] = u.fi + v.fi;
                    pq.push({dp[v.se][mask], v.se});
                }
            }
        }
    }
}
int main()
{
    if(fopen(task".in", "r"))
    {
       freopen(task".in", "r", stdin);
       freopen(task".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int ntest = 1;
    //cin >> ntest;
    while(ntest -- > 0)
    sol();
}
/*
4 5 2
10 9 5 2
6 4 20 15
9 7 10 9
-1 -1 16 11
1 2 3
2 3 3
1 4 1
4 3 1
3 1 1

*/

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:85:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |        freopen(task".in", "r", stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
cities.cpp:86:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |        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