Submission #917739

#	Time	Username	Problem	Language	Result	Execution time	Memory
917739		406	Robot (JOI21_ho_t4)	C++17	24 / 100	171 ms	51784 KiB

Main

#include <bits/stdc++.h>
#define int int64_t
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)

using namespace std;
using ar = array<int, 2>;
using ar3 = array<int, 3>;

const int64_t INF = 1ll << 60;
const int N = 2e5 + 5;

vector<ar3> adj[N];
int n, m, C[N], d[N], cnt[N];
ar last[N];

signed main() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr); 
        cin >> n >> m;
        FOR(i, 0, m) {
                int u, v, c, p;
                cin >> u >> v >> c >> p;
                --u, --v;
                adj[v].push_back({u, c, p});
                adj[u].push_back({v, c, p});
        }
        fill(last, last + N, ar{-1, -1});

        vector<array<int, 4>> E;
        FOR(i, 0, n) {
                for (auto [u, c, p]: adj[i]) cnt[c]++;
                for (auto &[u, c, p]: adj[i]) {
                        if (cnt[c] == 1) p = 0;
                        if (cnt[c] == 2) {
                                if (last[c][0] == -1) last[c] = {u, p};
                                else {
                                        E.push_back({u, last[c][0], c, last[c][1]});
                                        E.push_back({last[c][0], u, c, p});
                                }
                        }
                }
                for (auto [u, c, p]: adj[i]) cnt[c] = 0, last[c][0] = -1;
        }
        for (auto [u, v, c, p]: E)
                adj[u].push_back({v, c, p});

        fill(d + 1, d + N, INF);
        queue<int> q;
        q.push(0);
        while (q.size()) {
                int v = q.front();
                q.pop();
                for (auto [u, c, p]: adj[v]) {
                        int w = d[v] + p;
                        if (w < d[u]) {
                                q.push(u);
                                d[u] = w;
                        }
                }
        }
        cout << (d[n - 1] < INF ? d[n - 1] : -1) << '\n';
        return 0;
}

• Subtask 1: 0 / 34
• Subtask 2: 24 / 24
• Subtask 3: 0 / 42