Submission #1245782

#	Time	Username	Problem	Language	Result	Execution time	Memory
1245782		vuxxcode	Cities (BOI16_cities)	C++20	14 / 100	279 ms	45224 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;
#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;

ll n, k, m, a [maxK], f [maxK] [1 << maxK], f2 [maxN] [1 << maxK], f3 [1 << maxK];
vector <pll> adj [maxN];
priority_queue <pll, vector <pll>, greater <pll>> q;
vector <ll> dij [maxK];

vector <ll> getdijk (ll x) {
    vector <ll> ans (n + 1, inf64);
    ans [x] = 0;
    q. push ({ans [x], x});
    while (!q. empty ()) {
        ll d = q. top (). fi;
        ll pos = q. top (). se;
        q. pop ();
        if (d != ans [pos]) continue;
        for (pll i : adj [pos]) {
            if (ans [i. fi] > ans [pos] + i. se) {
                ans [i. fi] = ans [pos] + i. se;
                q. push ({ans [i. fi], i. fi});
            }
        }
    }
    return ans;
}

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});
    }
    for (int i = 0; i < k; i ++) {
        dij [i] = getdijk (a [i]);
    }
    memset (f, 0x3f, sizeof f);
    for (int i = 0; i < k; i ++) f [i] [1 << i] = 0;
    for (int i = 0; i < (1 << k); i ++) {
        for (int on = 0; on < k; on ++) if ((i >> on) & 1) {
            for (int off = 0; off < k; off ++) if (((~i) >> on) & 1) {
                mini (f [off] [i | (1 << off)],
                      f [on] [i] + dij [on] [a [off]]);
            }
        }
    }
    ll ans = inf64;
    for (int i = 0; i < k; i ++) mini (ans, f [i] [(1 << k) - 1]);
    memset (f3, 0x3f, sizeof f3);
    for (int i = 0; i < (1 << k); i ++) {
        for (int j = 1; j <= n; j ++) {

            for (int bit = 0; bit < k; bit ++) if ((i >> bit) & 1) {
                f2 [j] [i] += dij [bit] [j];
            }
            mini (f3 [i], f2 [j] [i]);
        }
    }
    for (int i = 0; i < (1 << k); i ++){
        for (int j = 0; j < k; j ++) if ((i >> j) & 1){
            ll br = (1 << k) - 1 - i;
            br += (1 << j);
            mini (ans, f3 [i] + f [j] [br]);
            mini (ans, f3 [i] + f3 [br]);
        }
    }
    cout << ans;
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:45:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
cities.cpp:46:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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