Submission #535744

#	Time	Username	Problem	Language	Result	Execution time	Memory
535744		sam571128	Robot (JOI21_ho_t4)	C++17	0 / 100	45 ms	20496 KiB

Main

#include <bits/stdc++.h>

#define int long long
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

using namespace std;

const int N = 1e3 + 5, M = 2e3 + 5;
struct edge {
    int v, c, p;
};

int dp[N][M], from[N][M];
vector<edge> adj[N];
map<int, int> sum[N];

signed main() {
    fastio
    int n, m;
    cin >> n >> m;

    for (int i = 0; i < m; i++) {
        int u, v, c, p;
        cin >> u >> v >> c >> p;
        adj[u].push_back({v, c, p});
        adj[v].push_back({u, c, p});
        sum[u][c] += p;
        sum[v][c] += p;
    }

    fill(&dp[0][0], &dp[N - 1][M - 1], 1e18);

    priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, greater<>> pq;
    dp[1][0] = 0;
    pq.push({0, {1, 0}});
    //dis, vertex, lst

    while (!pq.empty()) {
        auto [ww, pp] = pq.top();
        pq.pop();
        auto [u, cc] = pp;

        if (ww > dp[u][cc])
            continue;

        for (auto [v, c, p] : adj[u]) {
            //Dont change this edge, change all others
            if (cc != c) {
                if (dp[v][c] > dp[u][cc] + sum[u][c] - p) {
                    dp[v][c] = dp[u][cc] + sum[u][c] - p;
                    from[v][c] = p;
                    pq.push({dp[v][c], {v, c}});
                }
            }

            //Change this edge, using p
            {
                if (dp[v][0] > dp[u][cc] + p) {
                    dp[v][0] = dp[u][cc] + p;
                    pq.push({dp[v][0], {v, 0}});
                }
            }
        }
    }

    int ans = 1e18;

    for (int i = 0; i <= m; i++) {
        ans = min(ans, dp[n][i]);
    }

    cout << (ans == 1e18 ? -1 : ans) << "\n";
}

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