Submission #1308787

#	Time	Username	Problem	Language	Result	Execution time	Memory
1308787		nvc2k8	Cities (BOI16_cities)	C++20	74 / 100	6096 ms	165704 KiB

cities

#include <bits/stdc++.h>
#define TASK "cities"
#define endl mmm
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define BIT(i,x) (((i)>>(x))&1)
#define FOR(i,a,b) for(int i = (a); i<=(b); i++)
#define FORD(i,a,b) for(int i = (a); i>=(b); i--)
#define all(C) (C).begin(), (C).end()
using namespace std;
using ll = long long;
using pii = pair<int,int>;
const int INT_LIM = 2147483647;
const ll LL_LIM = 9223372036854775807;
template <typename X> bool minimize(X &x, const X &y) {if (x>y){x = y; return true;}return false;}
template <typename X> bool maximize(X &x, const X &y) {if (x<y){x = y; return true;}return false;}
///------------------------------------------///
const int maxn = 1e5+5;
int n, m, k;
int a[6], dd[maxn];
vector<pii> adj[maxn];

void inp()
{
    cin >> n >> k >> m;
    FOR(i, 1, n) dd[i] = 10;
    FOR(i, 1, k)
    {
        cin >> a[i];
        dd[a[i]] = i-1;
    }

    FOR(i, 1, m)
    {
        int u,v,c;
        cin >> u >> v >> c;
        adj[u].pb(mp(v,c));
        adj[v].pb(mp(u,c));
    }
}

ll dp[maxn][32];

void solve()
{
    priority_queue<pair<ll,pii>, vector<pair<ll,pii>>, greater<pair<ll,pii>>> q;

    FOR(i, 1, n) FOR(mask, 1, (1<<k)-1)
    {
        dp[i][mask] = LL_LIM;
        if (__builtin_popcount(mask)==1 && BIT(mask,dd[i]))
        {
            dp[i][mask] = 0;
            q.push(mp(0,mp(i,mask)));
        }
    }

    ll ans = LL_LIM;

    while (!q.empty())
    {
        ll d = q.top().fi;
        int u = q.top().se.fi, mask = q.top().se.se;
        q.pop();
        if (dp[u][mask]<d) continue;
        if (mask==(1<<k)-1) minimize(ans, d);
//        cout << u << ' ';
//        FOR(i, 0, k-1) cout << BIT(mask,i);
//        cout << ' ';
//        cout << d << '\n';

        for (auto V:adj[u])
        {
            int v = V.fi, c = V.se;
            FOR(mask2, 0, (1<<k)-1) if (dp[v][mask2]!=LL_LIM)
            {
                ll val = d+c+dp[v][mask2];
                if (minimize(dp[v][mask|mask2], val))
                {
                    q.push(mp(val, mp(v,mask|mask2)));
                }
            }
        }
    }
    cout << ans;
}

signed main()
{
    ///--------------------------///
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    if (fopen(TASK".INP","r")!=NULL)
    {
        freopen(TASK".INP","r",stdin);
        freopen(TASK".OUT","w",stdout);
    }
    ///--------------------------///

    int NTEST = 1;
    bool multitest = 0;
    if (multitest) cin >> NTEST;

    while (NTEST--)
    {
        inp();
        solve();
    }

    return 0;
}

///------------------------------------------///

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:96:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         freopen(TASK".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
cities.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen(TASK".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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