Submission #1150586

#	Time	Username	Problem	Language	Result	Execution time	Memory
1150586		nguyn	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	320 ms	78836 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define endl '\n'
#define pii pair<int, int>
#define F first
#define S second
#define pb push_back

const int N = 2e5 + 5;
const int inf = 1e18;

int n, m;
vector<pii> g[N];
int a, b, c, dd;
int d[4 * N];
int da[N];
int db[N];
vector<pii> gr[4 * N];
priority_queue<pii, vector<pii>, greater<pii>> pq;

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (fopen("INP.INP" ,"r")) {
        freopen("INP.INP" ,"r" , stdin) ;
        freopen("OUT.OUT" , "w" , stdout) ;
    }
    cin >> n >> m;
    cin >> a >> b >> c >> dd;
    for (int i = 1; i <= m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].pb({v, w});
        g[v].pb({u, w});
    }
    for (int i = 1; i <= n; i++) {
        d[i] = inf;
    }
    d[a] = 0;
    pq.push({0, a});
    while(!pq.empty()) {
        int du = pq.top().F;
        int u = pq.top().S;
        pq.pop();
        if (du != d[u]) continue;
        for (auto it : g[u]) {
            int w = it.S;
            int v = it.F;
            if (d[v] > d[u] + w) {
                d[v] = d[u] + w;
                pq.push({d[v], v});
            }
        }
    }
    for (int i = 1; i <= n; i++) {
        da[i] = d[i];
        d[i] = inf;
    }
    d[b] = 0;
    pq.push({0, b});
    while(!pq.empty()) {
        int du = pq.top().F;
        int u = pq.top().S;
        pq.pop();
        if (du != d[u]) continue;
        for (auto it : g[u]) {
            int w = it.S;
            int v = it.F;
            if (d[v] > d[u] + w) {
                d[v] = d[u] + w;
                pq.push({d[v], v});
            }
        }
    }
    for (int i = 1; i <= n; i++) {
        db[i] = d[i];
    }
    for (int u = 1; u <= n; u++) {
        gr[u].pb({n + u, 0});
        gr[u].pb({2 * n + u, 0});
        gr[n + u].pb({3 * n + u, 0});
        gr[2 * n + u].pb({3 * n + u, 0});
        for (auto it : g[u]) {
            int v = it.F;
            int w = it.S;
            if (da[u] + w + db[v] == da[b]) {
                gr[n + u].pb({n + v, 0});
                gr[2 * n + v].pb({2 * n + u, 0});
            }
            gr[u].pb({v, w});
            gr[3 * n + u].pb({3 * n + v, w});
        }
    }
    for (int i = 1; i <= 4 * n; i++) d[i] = inf;
    d[c] = 0;
    pq.push({0, c});
    while(!pq.empty()) {
        int du = pq.top().F;
        int u = pq.top().S;
        pq.pop();
        if (du != d[u]) continue;
        for (auto it : gr[u]) {
            int v = it.F;
            int w = it.S;
            if (d[v] > d[u] + w) {
                d[v] = d[u] + w;
                pq.push({d[v], v});
            }
        }
    }
    cout << d[3 * n + dd];
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen("INP.INP" ,"r" , stdin) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:28:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |         freopen("OUT.OUT" , "w" , stdout) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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