Submission #955382

#	Time	Username	Problem	Language	Result	Execution time	Memory
955382		blackslex	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	235 ms	27444 KiB

commuter_pass

#include<bits/stdc++.h>

using namespace std;
using ll = long long;
using pii = pair<ll, ll>;

int n, m, s, t, cs, ct, x, y, z;

int main() {
    scanf("%d %d %d %d %d %d", &n, &m, &s, &t, &cs, &ct);
    vector<vector<pii>> v(n + 5, vector<pii>());
    while (m--) scanf("%d %d %d", &x, &y, &z), v[x].emplace_back(y, z), v[y].emplace_back(x, z);
    vector<ll> d(n + 5, 1e18);
    vector<vector<int>> par(n + 5, vector<int>());
    priority_queue<pii, vector<pii>, greater<pii>> pq;
    pq.emplace(d[s] = 0, s);
    while (!pq.empty()) {
        auto [nd, nn] = pq.top(); pq.pop();
        for (auto &[tn, td]: v[nn]) {
            if (d[tn] > d[nn] + td) par[tn].clear(), par[tn].emplace_back(nn), pq.emplace(d[tn] = d[nn] + td, tn);
            else if (d[tn] == d[nn] + td) par[tn].emplace_back(nn);
        }
    }
    vector<int> u{t};
    for (int i = 0; i < u.size(); i++) {
        for (auto &e: par[u.back()]) u.emplace_back(e);
    }
    for (auto &e: u) v[n + 1].emplace_back(e, 0), v[e].emplace_back(n + 1, 0);
    vector<ll> d2(n + 5, 1e18);
    pq.emplace(d2[cs] = 0, cs);
    while (!pq.empty()) {
        auto [nd, nn] = pq.top(); pq.pop();
        for (auto &[tn, td]: v[nn]) if (d2[tn] > d2[nn] + td) pq.emplace(d2[tn] = d2[nn] + td, tn);
    }
    printf("%lld", d2[ct]);
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:25:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |     for (int i = 0; i < u.size(); i++) {
      |                     ~~^~~~~~~~~~
commuter_pass.cpp:10:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     scanf("%d %d %d %d %d %d", &n, &m, &s, &t, &cs, &ct);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:12:22: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |     while (m--) scanf("%d %d %d", &x, &y, &z), v[x].emplace_back(y, z), v[y].emplace_back(x, z);
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45