Submission #667516

#	Time	Username	Problem	Language	Result	Execution time	Memory
667516		Reb007	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	669 ms	31732 KiB

commuter_pass

// clang-format off
#include <bits/stdc++.h>

using namespace std;
mt19937 rnd(time(0));
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("fast-math")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
#define int long long
#define ll long long
#define ld long double
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
const long long INF = 20000000000000000;
const int inf = 1000000010;
const int maxn = 262144;
const int mxlg = 20;
const double eps = 1e-13;
int mod = 1e9 + 9;
const int C = 340;
vector<vector<pair<int, int>>> eds;
int n;

void dij(vector<vector<int>> &p, int s) {
    vector<int> dp(n, INF);
    dp[s] = 0;
    set<pair<int, int>> buf;
    buf.insert({0, s});
    while (!buf.empty()) {
        int v = buf.begin()->second;
        buf.erase(buf.begin());
        for (auto [to, c]: eds[v]) {
            if (dp[v] + c < dp[to]) {
                buf.erase({dp[to], to});
                dp[to] = dp[v] + c;
                p[to].clear();
                p[to].push_back(v);
                buf.insert({dp[to], to});
            } else if (dp[v] + c == dp[to]) {
                p[to].push_back(v);
            }
        }
    }
}
vector<int> ans;
void dij2(vector<vector<int>> &p, int s) {
    ans.assign(n, INF);
    ans[s] = 0;
    set<pair<int, int>> buf;
    buf.insert({0, s});
    while (!buf.empty()) {
        int v = buf.begin()->second;
        buf.erase(buf.begin());
        for (int to: p[v]) {
            if (ans[v] < ans[to]) {
                buf.erase({ans[to], to});
                ans[to] = ans[v];
                buf.insert({ans[to], to});
            }
        }
        for (auto [to, c]: eds[v]) {
            if (ans[v] + c < ans[to]) {
                buf.erase({ans[to], to});
                ans[to] = ans[v] + c;
                buf.insert({ans[to], to});
            }
        }
    }
}
vector<int> buf;
void del(vector<vector<int>> &p, int s, int t){
    buf.push_back(s);
    vector<bool> used(n);
    used[s] = 1;
    while(!buf.empty()){
        int v = buf.back();
        buf.pop_back();
        for(int to:p[v]){
            if(!used[to]){
                used[to] = 1;
                buf.push_back(to);
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        if(!used[i])p[i].clear();
    }
}
void solve() {
    int m, s, t, v, u;
    cin >> n >> m >> s >> t >> v >> u;
    --s, --t, --v, --u;
    eds.resize(n);
    for (int i = 0; i < m; ++i) {
        int x, y, c;
        cin >> x >> y >> c;
        --x, --y;
        eds[x].push_back({y, c});
        eds[y].push_back({x, c});
    }
    vector<vector<int>> st(n);
    vector<vector<int>> ts(n);
    dij(st, s);
    del(st, t, s);
    dij(ts, t);
    del(ts, s, t);
    int mn = INF;
    dij2(st, v);
    mn = min(mn, ans[u]);
    dij2(ts, v);
    mn = min(mn, ans[u]);
    cout << mn << '\n';
}

signed main() {
//    freopen("kthzero.in", "r", stdin);
//    freopen("kthzero.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int __ = 1;
//    cin >> __;
    while (__--)
        solve();
    return 0;
}

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