Submission #924801

#	Time	Username	Problem	Language	Result	Execution time	Memory
924801		yeediot	Olympic Bus (JOI20_ho_t4)	C++14	100 / 100	781 ms	7616 KiB

ho_t4

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define sz(x) (int)(x.size())
#define all(x) x.begin(),x.end()
#define F first
#define S second
#define pb push_back
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
struct edge{
    int a,b,c,d;
};
const int mxn=405;
const int inf=1e15;
vector<edge>e;
int from[5][mxn];
int dis[5][mxn];
vector<pii>adj[2][mxn];
vector<pii>adj2[mxn];
bool used[500005];
int n;
void dij(int st,int p,int type){
    for(int i=0;i<mxn;i++){
        dis[p][i]=inf;
        from[p][i]=-1;
    }
    dis[p][st]=0;
    priority_queue<pii,vector<pii>,greater<pii>>pq;
    pq.push({0,st});
    while(sz(pq)){
        auto [dist,v]=pq.top();
        pq.pop();
        if(dist>dis[p][v])continue;
        if(from[p][v]!=-1)used[from[p][v]]=1;
        for(auto [u,id]:adj[type][v]){
            int w=e[id].c;
            if(dist+w<dis[p][u]){
                dis[p][u]=dist+w;
                pq.push({dis[p][u],u});
                from[p][u]=id;
            }
        }
    }
}
int dij2(int st,int ed,int p,int i){
    for(int i=0;i<mxn;i++){
        dis[p][i]=inf;
        from[p][i]=inf;
    }
    dis[p][st]=0;
    priority_queue<pii,vector<pii>,greater<pii>>pq;
    pq.push({0,st});
    while(sz(pq)){
        auto [dist,v]=pq.top();
        pq.pop();
        if(dist>dis[p][v])continue;
        for(auto [u,id]:adj2[v]){
            if(id==i and e[id].a==v)continue;
            int w=e[id].c;
            if(dist+w<dis[p][u]){
                dis[p][u]=dist+w;
                pq.push({dis[p][u],u});
            }
        }
    }
    return dis[p][ed];
}
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    setio();
    int m;
    cin>>n>>m;
    for(int i=0;i<m;i++){
        int a,b,c,d;
        cin>>a>>b>>c>>d;
        e.pb({a,b,c,d});
        adj[0][a].pb({b,i});
        adj2[a].pb({b,i});
        adj[1][b].pb({a,i});
    }
    dij(1,0,0);
    dij(1,1,1);
    dij(n,2,0);
    dij(n,3,1);
    int ans=dis[0][n]+dis[2][1];
    for(int i=0;i<m;i++){
        auto [a,b,c,d]=e[i];
        if(used[i]){
            e[i].c+=d;
            adj2[b].pb({a,i});
            ans=min(ans,dij2(1,n,4,i)+dij2(n,1,4,i));
            adj2[b].pop_back();
            e[i].c-=d;
        }
        else{
            ans=min(ans,min(dis[0][n],dis[0][b]+c+dis[3][a])+min(dis[2][1],dis[2][b]+dis[1][a]+c)+d);
        }
    }
    if(ans>=(int)1e15){
        cout<<-1<<'\n';
        return 0;
    }
    cout<<ans<<'\n';
}
/*
*/
 
 

Compilation message (stderr)

ho_t4.cpp: In function 'void dij(long long int, long long int, long long int)':
ho_t4.cpp:38:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   38 |         auto [dist,v]=pq.top();
      |              ^
ho_t4.cpp:42:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   42 |         for(auto [u,id]:adj[type][v]){
      |                  ^
ho_t4.cpp: In function 'long long int dij2(long long int, long long int, long long int, long long int)':
ho_t4.cpp:61:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   61 |         auto [dist,v]=pq.top();
      |              ^
ho_t4.cpp:64:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   64 |         for(auto [u,id]:adj2[v]){
      |                  ^
ho_t4.cpp: In function 'int main()':
ho_t4.cpp:95:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   95 |         auto [a,b,c,d]=e[i];
      |              ^

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