Submission #1141464

#	Time	Username	Problem	Language	Result	Execution time	Memory
1141464		buzdi	Robot (JOI21_ho_t4)	C++17	34 / 100	3094 ms	45480 KiB

Main

#include <bits/stdc++.h>

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
#define ll long long
#define ld long double

using namespace std;
using namespace __gnu_pbds;

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

const int NMAX = 1e5;
const ll INF = 1e18;

struct Edge {
    int to, c, p;
    Edge(int to, int c, int p) : to(to), c(c), p(p) {}
};

struct PQElement {
    int node, c;
    ll cost;
    bool operator < (const PQElement &other) const {
        return other.cost < cost;
    }
};

int n, m;
vector<Edge> g[NMAX + 1];
ll dp[NMAX + 1];
map<int, ll> sum[NMAX + 1];
map<int, ll> dp1[NMAX + 1];

void Dijkstra() {
    for(int i = 1; i <= n; i++) {
        dp[i] = INF;
    }

    priority_queue<PQElement> pq;
    pq.push({1, 0, 0});
    while(!pq.empty()) {
        auto [node, c, cost] = pq.top();
        pq.pop();

        // cout << node << ' ' << c << ' ' << cost << '\n';

        if(!c) {
            if(dp[node] != INF) {
                continue;
            }
            dp[node] = cost;

            for(auto [next_node, edge_c, p] : g[node]) {
                // I change the colour of the edge
                pq.push({next_node, 0, cost + p});

                // I change every edge that has this edge colour
                pq.push({next_node, 0, cost + (sum[node][edge_c] - p)});

                // I change the colour of the edge and all of the same-coloured edges of next_node with this colour
                // I compute this when I am at next_node
                pq.push({next_node, edge_c, cost});
            }
        }
        else {
            if(dp1[node].count(c)) {
                continue;
            }
            dp1[node][c] = cost;

            for(auto [next_node, edge_c, p] : g[node]) {
                if(edge_c != c) {
                    continue;
                }

                // I can only change every edge that has this edge colour
                pq.push({next_node, 0, cost + (sum[node][c] - p)});
            }
        }
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> m;
    for(int i = 1; i <= m; i++) {
        int a, b, c, p;
        cin >> a >> b >> c >> p;
        g[a].emplace_back(b, c, p);
        g[b].emplace_back(a, c, p);

        sum[a][c] += p;
        sum[b][c] += p;
    }

    // for(auto [a, b, c] : g[1]) {
        // cout << a << ' ' << b << ' ' << c << '\n'; 
    // }


    Dijkstra();
    // for(int i = 1; i <= n; i++) {
    //     cout << dp[i] << '\n';
    // }
    // cout << '\n';
    cout << (dp[n] == INF ? -1 : dp[n]);

    return 0;
}

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