Submission #924758

#	Time	Username	Problem	Language	Result	Execution time	Memory
924758		yeediot	Olympic Bus (JOI20_ho_t4)	C++14	0 / 100	152 ms	6924 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;
vector<edge>e;
vector<int>temp;
pii w[mxn][mxn];
pii w2[mxn][mxn];
int id[mxn];
vector<bool>check(50005);
vector<int> dij(int st,int n,bool tf){
    vector<int>dis(mxn);
    for(int i=0;i<mxn;i++)dis[i]=1e15;
    dis[st]=0;
    if(tf){
        for(int i=1;i<=n;i++){
            id[i]=-1;
        }
    }
    vector<bool>used(n+1,0);
    for(int i=1;i<=n;i++){
        int t=-1;
        for(int j=1;j<=n;j++){
            if(used[j])continue;
            if(t==-1 or dis[j]<dis[t]){
                t=j;
            }
        }
        used[t]=1;
        for(int j=1;j<=n;j++){
            if(dis[t]+w[t][j].F<dis[j]){
                dis[j]=dis[t]+w[t][j].F;
                if(!tf)continue;
                if(id[j]!=-1){
                    check[id[j]]=0;
                    continue;
                }
                id[j]=w[t][j].S;
                check[id[j]]=1;
            }
        }
    }
    return dis;
}
vector<int> rdij(int st,int n,bool tf){
    vector<int>dis(mxn);
    for(int i=0;i<mxn;i++)dis[i]=1e15;
    dis[st]=0;
    if(tf){
        for(int i=1;i<=n;i++){
            id[i]=-1;
        }
    }
    vector<bool>used(n+1,0);
    for(int i=1;i<=n;i++){
        int t=-1;
        for(int j=1;j<=n;j++){
            if(used[j])continue;
            if(t==-1 or dis[j]<dis[t]){
                t=j;
            }
        }
        used[t]=1;
        for(int j=1;j<=n;j++){
            if(dis[t]+w[j][t].F<dis[j]){
                dis[j]=dis[t]+w[j][t].F;
                if(!tf)continue;
                if(id[j]!=-1){
                    check[id[j]]=0;
                    continue;
                }
                id[j]=w[j][t].S;
                check[id[j]]=1;
            }
        }
    }
    return dis;
}
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    setio();
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            w[i][j]={1e15,1e15};
            w2[i][j]={1e15,1e15};
        }
    }
    for(int i=0;i<m;i++){
        int a,b,c,d;
        cin>>a>>b>>c>>d;
        e.pb({a,b,c,d});
        if(c<w[a][b].F or (c==w[a][b].F and d<e[w[a][b].S].d)){
            w2[a][b]=w[a][b];
            w[a][b]={c,i};
        }
        else if(c<w2[a][b].F or (c==w2[a][b].F and d<e[w2[a][b].S].d)){
            w2[a][b]={c,i};
        }
    }
    vector<int>dd=dij(1,n,1);
    vector<int>dd2=rdij(1,n,1);
    vector<int>rd2=rdij(n,n,1);
    vector<int>rd=dij(n,n,1);
    int ans=dd[n]+rd[1];
    for(int i=0;i<m;i++){
        //cout<<check[i]<<'\n';
        auto [a,b,c,d]=e[i];
        if(check[i]){
            auto x=w[a][b];
            if(w[a][b].S==i){
                if(w2[a][b]!=make_pair((int)1e15,(int)1e15)){
                    w[a][b]=w2[a][b];
                }
            }
            auto y=w[b][a];
            w[b][a].F=min(w[b][a].F,c+d);
            ans=min(ans,dij(1,n,0)[n]+dij(n,n,0)[1]);
            w[a][b]=x;
            w[b][a]=y;
        }
        else{
            ans=min(ans,min(dd[b]+c+rd[a],dd[n])+min(rd[1],rd[b]+c+dd[a])+d);
        }
        //cout<<ans<<'\n';
    }
    if(ans>=1e15){
        cout<<-1<<'\n';
        return 0;
    }
    cout<<ans<<'\n';
}
/*
*/

Compilation message (stderr)

ho_t4.cpp: In function 'int main()':
ho_t4.cpp:126:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  126 |         auto [a,b,c,d]=e[i];
      |              ^

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