Submission #1143704

#	Time	Username	Problem	Language	Result	Execution time	Memory
1143704		poltanos	Robot (JOI21_ho_t4)	C++20	100 / 100	1018 ms	82552 KiB

Main

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

const int inf = 1e18;

struct edge {
    int to, c;
    int p;
};

vector<map<int, vector<edge>>> graph(1e5 + 1);
vector<int> dp(1e5 + 1, inf);
vector<map<int, int>> dp2(1e5 + 1), psum(1e5 + 1);

void solve() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= m; i++) {  // FIX: Loop should start from 1 to match correct code
        int u, v, c;
        int p;
        cin >> u >> v >> c >> p;
        graph[u][c].push_back({v, c, p});
        graph[v][c].push_back({u, c, p});
        psum[u][c] += p;
        psum[v][c] += p;
    }

    fill(dp.begin(), dp.end(), 0x3f3f3f3f3f3f3f3f); // FIX: Correct way to initialize large values
    dp[1] = 0;
    priority_queue<tuple<int, int, int>> pq;
    pq.push({0, 1, 0});

    while (!pq.empty()) {
        int cost, node, c;
        tie(cost, node, c) = pq.top();
        pq.pop();

        if (c) {
            if (dp2[node][c] != -cost) continue;
            for (edge i : graph[node][c]) {
                int case1 = psum[node][c] - i.p;
                if (case1 - cost < dp[i.to]) {
                    dp[i.to] = case1 - cost;
                    pq.push({-dp[i.to], i.to, 0});
                }
            }
        } else {
            if (dp[node] != -cost) continue;
            for (auto &i : graph[node]) {
                for (edge j : i.second) {
                    int case1 = psum[node][j.c] - j.p - cost;
                    if (case1 < dp[j.to]) {
                        dp[j.to] = case1;
                        pq.push({-dp[j.to], j.to, 0});
                    }

                    int case2 = j.p - cost;
                    if (case2 < dp[j.to]) {
                        dp[j.to] = case2;
                        pq.push({-dp[j.to], j.to, 0});
                    }

                    int case3 = -cost;
                    if (!dp2[j.to].count(j.c) || case3 < dp2[j.to][j.c]) {
                        dp2[j.to][j.c] = case3;
                        pq.push({-dp2[j.to][j.c], j.to, j.c});
                    }
                }
            }
        }
    }

    cout << (dp[n] > inf ? -1 : dp[n]) << endl;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    solve();
    return 0;
}

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