Submission #535723

#	Time	Username	Problem	Language	Result	Execution time	Memory
535723		sam571128	Robot (JOI21_ho_t4)	C++17	0 / 100	8 ms	16196 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 = 1;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