Submission #1265195

#	Time	Username	Problem	Language	Result	Execution time	Memory
1265195		nhathanh	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	233 ms	19048 KiB

commuter_pass

    #include<bits/stdc++.h>
using namespace std;
#define el "\n"
#define pii pair<int,int>
#define fi first
#define se second
#define int long long
#define file(name) if(fopen(name".inp","r")){freopen(name".inp","r",stdin);freopen(name".out","w",stdout);}
const int N=1e5+10;
const int M=2e5+10;
int n,m,s,t,u,v,ans=LLONG_MAX;
int du[N],dv[N],dis[N],dp[2][N];
int a,b,c;
vector<pii>g[N];
class cmp
{
public:
    bool operator()(pii x,pii y)
    {
        return x.se>y.se;
    }
};
priority_queue<pii,vector<pii>,cmp>temp;

void dij(int x,int arr[])
{
   fill(arr,arr+n+1,1e15);
   arr[x]=0;
   temp.push({x,0LL});

   while(!temp.empty())
   {
       pii p=temp.top();
       temp.pop();
       for(pii z : g[p.fi])
       {
           if(arr[z.fi]<=arr[p.fi]+z.se) continue;
           arr[z.fi]=arr[p.fi]+z.se;
           temp.push({z.fi,arr[z.fi]});
       }
   }
}

void dijktra(int st,int ed)
{
    fill(dp[1],dp[1]+n+1,1e15);
    fill(dp[0],dp[0]+n+1,1e15);
    fill(dis,dis+1+n,1e15);
    dis[st]=0;
    dp[0][st]=du[st];
    dp[1][st]=dv[st];
    temp.push({st,0});

    while(!temp.empty())
    {
        pii p=temp.top();
        temp.pop();
        for(pii z : g[p.fi])
        {
            if(dis[z.fi]<dis[p.fi]+z.se) continue;
            if(dis[z.fi]>dis[p.fi]+z.se)
            {
                dis[z.fi]=dis[p.fi]+z.se;
                dp[0][z.fi]=min(du[z.fi],dp[0][p.fi]);
                dp[1][z.fi]=min(dv[z.fi],dp[1][p.fi]);
                temp.push({z.fi,dis[z.fi]});
            }
            else if(min(du[z.fi],dp[0][p.fi])+min(dv[z.fi],dp[1][p.fi])<=dp[0][z.fi]+dp[1][z.fi])
            {
                dp[0][z.fi]=min(du[z.fi],dp[0][p.fi]);
                dp[1][z.fi]=min(dv[z.fi],dp[1][p.fi]);
            }
        }
    }

    ans=min(ans,dp[0][ed]+dp[1][ed]);
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    file("a");

    cin>>n>>m>>s>>t>>u>>v;

    for(int i=1;i<=m;i++)
    {
        cin>>a>>b>>c;
        g[a].push_back({b,c});
        g[b].push_back({a,c});
    }

    dij(u,du); dij(v,dv);

    dijktra(s,t);
    dijktra(t,s);
    ans=min(ans,du[v]);
    cout<<ans;
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:8:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 | #define file(name) if(fopen(name".inp","r")){freopen(name".inp","r",stdin);freopen(name".out","w",stdout);}
      |                                              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:82:5: note: in expansion of macro 'file'
   82 |     file("a");
      |     ^~~~
commuter_pass.cpp:8:83: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 | #define file(name) if(fopen(name".inp","r")){freopen(name".inp","r",stdin);freopen(name".out","w",stdout);}
      |                                                                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:82:5: note: in expansion of macro 'file'
   82 |     file("a");
      |     ^~~~

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