Submission #1123722

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123722		icebear	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	323 ms	23368 KiB

commuter_pass

// ~~ icebear love atttttttttttt ~~
#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<ii, int> iii;

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i, n) for(int i=0; i<(n); ++i)
#define red(i, n) for(int i=(n)-1; i>=0; --i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebearat"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll LLinf = 1e18 + 27092008;
const int N = 1e5 + 5;
int n, m, U, V, S, T;
vector<ii> G[N];
int dist[4][N], f[N][2], dp[N];
vector<int> adj[N];

void dijkstra(int id, int src) {
    priority_queue<ii, vector<ii>, greater<ii>> pq;
    memset(dist[id], 0x3f, sizeof dist[id]);
    dist[id][src] = 0;
    pq.push(mp(0, src));
    while(!pq.empty()) {
        int du, u; tie(du, u) = pq.top(); pq.pop();
        if (du != dist[id][u]) continue;
        for(ii e : G[u]) {
            int v, w; tie(v, w) = e;
            if (dist[id][v] > dist[id][u] + w) {
                dist[id][v] = dist[id][u] + w;
                pq.push(mp(dist[id][v], v));
            }
        }
    }
} 

int dijkstra2(int id, int src) {
    priority_queue<ii, vector<ii>, greater<ii>> pq;
    FOR(i, 1, n) {
        dist[id][i] = LLinf;
        f[i][0] = f[i][1] = LLinf;
    }
    dist[id][src] = 0;
    pq.push(mp(0, src));
    f[src][0] = dist[0][src];
    f[src][1] = dist[1][src]; 
    while(!pq.empty()) {
        int du, u;
        tie(du, u) = pq.top(); pq.pop();
        if (du != dist[id][u]) continue;
        for(ii e : G[u]) {
            int v, w; tie(v, w) = e;
            if (dist[id][v] > dist[id][u] + w) {
                dist[id][v] = dist[id][u] + w;
                f[v][0] = min(f[u][0], dist[0][v]);
                f[v][1] = min(f[u][1], dist[1][v]);
                pq.push(mp(dist[id][v], v));
            } else 
            if (dist[id][v] == dist[id][u] + w && min(dist[0][v], f[u][0]) + min(dist[1][v], f[u][1]) < f[v][0] + f[v][1]) {
                f[v][0] = min(dist[0][v], f[u][0]);
                f[v][1] = min(dist[1][v], f[u][1]);
            }
        }
    }
    return (src == S ? f[T][0] + f[T][1] : f[S][0] + f[S][1]);
}

void solve() {
    cin >> n >> m >> S >> T >> U >> V;  
    FOR(i, 1, m) {
        int u, v, w;
        cin >> u >> v >> w;
        G[u].pb(mp(v, w));
        G[v].pb(mp(u, w));
    }

    dijkstra(0, U);
    dijkstra(1, V);

    cout << min({dist[0][V], dijkstra2(2, S), dijkstra2(3, T)});
}

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

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.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".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45