Submission #224110

#	Time	Username	Problem	Language	Result	Execution time	Memory
224110		dwsc	Olympic Bus (JOI20_ho_t4)	C++14	5 / 100	138 ms	428 KiB

ho_t4

#include <bits/stdc++.h>
#define int long long
using namespace std;
typedef pair<int,int> ii;
typedef pair<ii,int> i3;
main(){
    int n,m;
    cin >> n >> m;
    if (m <= 1000){
        int ans = 1e18;
        i3 edges[m];
        int invert[m+1];
        for (int i = 0; i < m; i++) {
            cin >> edges[i].first.first >> edges[i].first.second >> edges[i].second;
            cin >> invert[i];
        }
        invert[m] = 0;
        for (int i = 0; i < m+1; i++){
            int temp = invert[i];
            vector<ii> tempadj[n+1];
            for (int j = 0; j < m; j++){
                if (j == i) tempadj[edges[j].first.second].push_back(ii(edges[j].first.first,edges[j].second));
                else tempadj[edges[j].first.first].push_back(ii(edges[j].first.second,edges[j].second));
            }
            int dist1[n+1],dist2[n+1];
            for (int j = 1; j <= n; j++) dist1[j] = dist2[j] = 1e18;
            priority_queue<ii,vector<ii>,greater<ii> >pq;
            pq.push(ii(0,1));
            dist1[1] = 0;
            while (!pq.empty()){
                ii f = pq.top();
                pq.pop();
                int d = f.first, u = f.second;
                if (d > dist1[u]) continue;
                for (int j = 0; j < tempadj[u].size(); j++){
                    ii v = tempadj[u][j];
                    if (dist1[u]+v.second < dist1[v.first]){
                        dist1[v.first] = dist1[u]+v.second;
                        pq.push(ii(dist1[v.first],v.first));
                    }
                }
            }
            pq.push(ii(0,n));
            dist2[n] = 0;
            while (!pq.empty()){
                ii f = pq.top();
                pq.pop();
                int d = f.first, u = f.second;
                if (d > dist2[u]) continue;
                for (int j = 0; j < tempadj[u].size(); j++){
                    ii v = tempadj[u][j];
                    if (dist2[u]+v.second < dist2[v.first]){
                        dist2[v.first] = dist2[u]+v.second;
                        pq.push(ii(dist2[v.first],v.first));
                    }
                }
            }
            ans = min(ans,temp+dist1[n]+dist2[1]);
        }
        if (ans == 1e18) cout << -1;
        else cout << ans;
    }
}

Compilation message (stderr)

ho_t4.cpp:6:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^
ho_t4.cpp: In function 'int main()':
ho_t4.cpp:35:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for (int j = 0; j < tempadj[u].size(); j++){
                                 ~~^~~~~~~~~~~~~~~~~~~
ho_t4.cpp:50:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for (int j = 0; j < tempadj[u].size(); j++){
                                 ~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63