Submission #1126637

#	Time	Username	Problem	Language	Result	Execution time	Memory
1126637		TVSown	Cities (BOI16_cities)	C++20	0 / 100	1198 ms	33240 KiB

cities

///*** Sown_Vipro ***///
/// ->NHI QUOC GIA<- ///

#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define REP(i, a, b) for(int i = a; i >= b; --i)
#define all(s) s.begin(), s.end()
#define szz(s) int(s.size())
const string NAME = "sown";
const int N = 1e6 + 5, MAX = 1e6, oo = 1e9 + 5, MOD = 1e9 + 7;
void maxi(int &x, int y){ if(x < y) x = y; }
void mini(int &x, int y){ if(x > y) x = y; };
void add(int &x, int y){ x += y; x += MOD * (x < 0); x -= MOD * (x >= MOD); };
int n, k, m;
int trace[N], spe[N];
long long d[N], dp[(1 << 5) + 5];
vector<pi> e[N];
vector<int> s[(1 << 5) + 5];

void dt(vector<int> &ss, int S, int A, int B){
    priority_queue<pair<long long, int> > pq;
    FOR(u, 1, n){
        d[u] = 1e18;
        trace[u] = 0;
    }
    for(int u : ss){
        d[u] = 0;
        pq.push({0, u});
    }

    while(pq.size()){
        int u = pq.top().S;
        long long du = -pq.top().F;
        pq.pop();
        if(du != d[u]) continue;
        if(u == S) break;
        for(auto [v, w] : e[u]){
            if(du + w < d[v]){
                d[v] = du + w;
                trace[v] = u;
                pq.push({-du - w, v});
            }
        }
    }
    if(dp[A] + d[S] >= dp[B]) return;
    dp[B] = dp[A] + d[S];
    s[B].clear();
    s[B] = s[A];
    while(trace[S]){
        s[B].pb(S);
        S = trace[S];
    }
}

void solve(){
    cin >> n >> k >> m;
    FOR(i, 1, k){
        int u; cin >> u;
        spe[i] = u;
        dp[u] = 0;
        s[(1 << i - 1)].pb(u);
    }

    FOR(i, 1, m){
        int u, v, w; cin >> u >> v >> w;
        e[u].pb({v, w});
        e[v].pb({u, w});
    }
//    FOR(i, 1, k) cout << spe[i] << "\n";
    priority_queue<pi, vector<pi>, greater<pi> > pq;
    FOR(mask, 1, (1 << k) - 1){
        if(s[mask].size()) continue;
        dp[mask] = 1e18;

        FOR(i, 1, k){
            if(mask & (1 << i - 1)){
//                cout << i << " " << spe[i] << "\n";
                dt(s[mask ^ (1 << i - 1)], spe[i], mask ^ (1 << i - 1), mask);
            }
        }
//        cout << dp[mask] << "\n";
    }
    cout << dp[(1 << k) - 1];
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    if(fopen((NAME + ".inp").c_str(), "r")){
        freopen((NAME + ".inp").c_str(), "r", stdin);
        freopen((NAME + ".out").c_str(), "w", stdout);
    }
    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:99:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |         freopen((NAME + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cities.cpp:100:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  100 |         freopen((NAME + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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