Submission #734755

#	Time	Username	Problem	Language	Result	Execution time	Memory
734755		bin9638	Travelling Merchant (APIO17_merchant)	C++17	0 / 100	8 ms	16380 KiB

merchant

#include <bits/stdc++.h>

using namespace std;

#define N 1010
#define ll long long
#define fs first
#define sc second
#define ii pair<ll,int>
#define pb push_back
#define int ll

int times,pos[N],low[N],tham[N],deg[N],dem,num[N],n,m,k,buy[N][N],sell[N][N],cost[N][N],dis[N][N],ktr[N][N];
vector<ii>g[N];
stack<int>st;

void visit(int u)
{
    low[u]=num[u]=++times;
    st.push(u);
    for(auto v:g[u])
        if(num[v.sc]!=0)
        {
            low[u]=min(low[u],num[v.sc]);
        }else
        {
            visit(v.sc);
            low[u]=min(low[u],low[v.sc]);
        }
    if(num[u]==low[u])
    {
     //   cout<<u<<endl;
        dem++;
        int k;
        do{
            k=st.top();
            st.pop();
            pos[k]=dem;
            low[k]=num[k]=1e9;
        }while(k!=u);
    }
}

ll get_cost(int u,int v)
{
    ll res=-1e18;
    for(int i=1;i<=k;i++)
        if(buy[u][i]!=-1&&sell[v][i]!=-1)
            res=max(res,sell[v][i]-buy[u][i]);
    return res;
}

void dijkstra(int S)
{
    priority_queue<ii>s;
    dis[S][S]=0;
    s.push({0,S});
    while(!s.empty())
    {
        ii cc=s.top();
        s.pop();
        ll L=-cc.fs;
        int u=cc.sc;
        if(ktr[S][u]==1)
            continue;
        ktr[S][u]=1;
        for(auto v:g[u])
            if(dis[S][v.sc]>L+v.fs)
            {
                dis[S][v.sc]=L+v.fs;
                s.push({-dis[S][v.sc],v.sc});
            }
    }
}

ii dp[N];

bool check(int X)
{
    //for(int i=1;i<=n;i++)cout<<pos[i]<<endl;
    times++;
    for(int i=1;i<=n;i++)
        dp[i]={-1e18,0};
    for(int i=1;i<=n;i++)
        if(tham[pos[i]]!=times)
        {
            dp[i]={0,0};
            tham[pos[i]]=times;
        }
    for(int t=1;t<=n;t++)
    {
        for(int u=1;u<=n;u++)
            for(int v=1;v<=n;v++)
                if(u!=v&&dis[u][v]<1e12)
                {
                    if(dp[v]<ii{dp[u].fs+cost[u][v]-dis[u][v]*X,dp[u].sc+1})
                        {
                            dp[v]=ii{dp[u].fs+cost[u][v]-dis[u][v]*X,dp[u].sc+1};
                           // cout<<u<<" "<<v<<" "<<dp[v].fs<<" "<<cost[u][v]<<" "<<dis[u][v]*X<<endl;
                        }
                  //  dp[v]=max(dp[v],ii{dp[u].fs+cost[u][v]-dis[u][v]*X,dp[u].sc+1});
                }
           //for(int i=1;i<=n;i++)cout<<dp[i].fs<<" "<<dp[i].sc<<endl;cout<<"cc\n";
    }
  //  for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)cout<<i<<" "<<j<<" "<<cost[i][j]<<endl;
    for(int u=1;u<=n;u++)
            for(int v=1;v<=n;v++)
                if(u!=v&&dis[u][v]<1e12)
                {
                        if(dp[v]<ii{dp[u].fs+cost[u][v]-dis[u][v]*X,dp[u].sc+1})
                            return 1;
                }
    return 0;
}

int32_t main()
{
    freopen("A.inp","r",stdin);
    freopen("A.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    cin>>n>>m>>k;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=k;j++)
            cin>>buy[i][j]>>sell[i][j];
    for(int i=1;i<=m;i++)
    {
        int u,v,L;
        cin>>u>>v>>L;
        g[u].pb({L,v});
     //   g[v].pb({L,u});
    }
    memset(cost,-0x3f3f,sizeof(cost));
    memset(dis,0x3f3f,sizeof(dis));
   // cout<<get_cost(1,2);return 0;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=n;j++)
            cost[i][j]=get_cost(i,j);
    for(int i=1;i<=n;i++)
        dijkstra(i);
    for(int i=1;i<=n;i++)
        if(num[i]==0)
            visit(i);
    //cout<<dem<<endl;
    //cout<<check(2)<<endl;
   // return 0;
    int l=1,r=1e9,res=0;
    while(l<=r)
    {
        int mid=(l+r)/2;
        if(check(mid))
        {
            res=mid;
            l=mid+1;
        }else
            r=mid-1;
    }
    cout<<res;
    return 0;
}

Compilation message (stderr)

merchant.cpp: In function 'int32_t main()':
merchant.cpp:118:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  118 |     freopen("A.inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~
merchant.cpp:119:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  119 |     freopen("A.out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 21
• Subtask 3: 0 / 33
• Subtask 4: 0 / 34