Submission #1035021

#	Time	Username	Problem	Language	Result	Execution time	Memory
1035021		_Nhm207_	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	276 ms	31232 KiB

commuter_pass

#include<bits/stdc++.h>
#define int long long
#define Task "bus"

using namespace std;

const int N = 1e5 + 5;

vector<int> ds , dt , du , dv;

int n , m , u , v , s , t , ok[N];

int res;

vector<pair<int , int>> g[N];

void dijkstra(int u , vector<int> &d){
    d . resize(n + 1);
    for(int i = 1 ; i <= n ; i++) d[i] = 1e18;
    d[u] = 0;
    priority_queue<pair<int , int> , vector<pair<int , int>> , greater<pair<int , int>>> pq;
    pq . push({d[u] , u});
    while(pq . size()){
        int u = pq . top() . second;
        int du = pq . top() . first;
        pq . pop();
        if(d[u] != du) continue;
        for(pair<int , int> nex : g[u]){
            if(d[nex . first] > d[u] + nex . second){
                d[nex . first] = d[u] + nex . second;
                pq . push({d[nex . first] , nex . first});
            }
        }
    }
}

void Get(int s , int t){
    vector<int> dp[2] , ds;
    dp[0] . resize(n + 1);
    dp[1] . resize(n + 1);
    ds . resize(n + 1); 
    for(int i = 0 ; i <= n ; i++) ds[i] = 1e18 , dp[0][i] = 1e18 , dp[1][i] = 1e18;
    ds[s] = 0;  
    memset(ok , false , sizeof(ok));
    priority_queue<pair<int , pair<int , int>> , vector<pair<int , pair<int , int>>> , greater<pair<int , pair<int , int>>>> pq;
    pq . push({0 , {s , 0}});
    while(pq . size()){
        int node , par;
        node = pq . top() . second . first;
        par = pq . top() . second . second;
        pq . pop();
        if(!ok[node]){
            ds[node] = pq . top() . first;
            dp[0][node] = min(dp[0][par] , du[node]);
            dp[1][node] = min(dp[1][par] , dv[node]);
            ok[node] = true;
            for(pair<int , int> nex : g[node]){
                pq . push({ds[node] + nex . second , {nex . first , node}});
            }
        }
        else if(pq . top() . first == ds[node] && min(dp[0][par] , du[node]) + min(dp[1][par] , dv[node]) <= dp[0][node] + dp[1][node]){
            dp[0][node] = min(dp[0][par] , du[node]);
            dp[1][node] = min(dp[1][par] , dv[node]);
        }
    }

    res = min(res , dp[0][t] + dp[1][t]);
}


int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    // if(fopen(Task".inp","r")){
    //     freopen(Task".inp","r",stdin);
    //     freopen(Task".out","w",stdout);
    // }
    cin >> n >> m;
    cin >> s >> t;
    cin >> u >> v;
    for(int i = 1 ; i <= m ; i++){
        int u , v , c;
        cin >> u >> v >> c;
        g[u] . push_back({v , c});
        g[v] . push_back({u , c});
    }
    dijkstra(u , du);
    dijkstra(v , dv);
    res = du[v];
    Get(s , t);
    Get(t , s);
    cout << res;
}

• Subtask 1: 0 / 16
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45