Submission #1245826

#	Time	Username	Problem	Language	Result	Execution time	Memory
1245826		vux2code	Cities (BOI16_cities)	C++20	100 / 100	1995 ms	71652 KiB

cities

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int, int> pii;
typedef pair<ll,pll> lll;
#define fi first
#define se second
void maxi (int &x, int y) {x = max (x, y);}
void mini (int &x, int y) {x = min (x, y);}

const ll maxN = 2e5 + 5, maxLog = 20, mod = 1e9 + 7, inf64 = 1e18, maxK = 5;

class Compare {
public:
	bool operator()(lll a, lll b) {
		if(a. se. se != b. se. se) return a. se. se > b. se. se;
		if(a. fi != b. fi) return a. fi > b. fi;
		return a. se. fi > b. se. fi;
	}
};

ll n, k, m, a [maxK], dij [maxN] [1 << maxK];
vector <pii> adj [maxN];
priority_queue <lll, vector <lll>, greater <lll>> q;

signed main () {
    ios::sync_with_stdio (0);
    cin. tie (0);
    cout. tie (0);
    #define task "untitled1"
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    cin >> n >> k >> m;
    for (int i = 0; i < k; i ++) cin >> a [i];
    for (int i = 1, u, v, w; i <= m; i ++) {
        cin >> u >> v >> w;
        adj [u]. push_back ({v, w});
        adj [v]. push_back ({u, w});
    }
    memset (dij, 0x3f, sizeof dij);
    for (int i = 0; i < k; i ++) {
        dij [a [i]] [1 << i] = 0;
    }
    for (int fk = 0; fk < (1 << k) - 1; fk ++) {
        for (int i = 1; i <= n; i ++) q. push ({dij [i][fk], {i, fk}});
        while (!q. empty ()) {
            ll dis = q. top (). fi;
            pll pos = q. top (). se;
            q. pop ();
            if (dis != dij [pos. fi] [pos. se]) continue;
            for (pll i : adj [pos. fi]) {
                if (dij [i. fi] [pos. se] > dij [pos. fi] [pos. se] + i. se) {
                    dij [i. fi] [pos. se] = dij [pos. fi] [pos. se] + i. se;
                    q. push ({dij [i. fi] [pos. se],  {i. fi, pos. se}});
                }
            }
        }
        for (int i = 1; i <= n; i ++) {
            for (int msk = 0; msk < (1 << k); msk ++) {
                if (fk & msk) continue;
                mini (dij [i] [msk | fk], dij [i] [msk] + dij [i] [fk]);
            }
        }
    }
    ll ans = inf64;
    for (int i = 1; i <= n; i ++) mini (ans, dij [i] [(1 << k) - 1]);
    cout << ans;
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:35:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
cities.cpp:36:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         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