Submission #734759

#	Time	Username	Problem	Language	Result	Execution time	Memory
734759		bin9638	Travelling Merchant (APIO17_merchant)	C++17	100 / 100	121 ms	20740 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 n,m,k,buy[N][N],sell[N][N],cost[N][N],dis[N][N],ktr[N][N];
vector<ii>g[N];

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++)
        dp[i]={0,0};
    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)
                {
                    dp[v]=max(dp[v],ii{dp[u].fs+max(0ll,cost[u][v])-dis[u][v]*X,dp[u].sc+1});
                }
    }
    //cout<<cost[1][4]<<endl;
   // for(int i=1;i<=n;i++)cout<<dp[i].fs<<" "<<dp[i].sc<<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+max(0ll,cost[u][v])-dis[u][v]*X,dp[u].sc+1})
                            return 1;
                }
    return 0;
}

int32_t main()
{
    #ifdef SKY
    freopen("A.inp","r",stdin);
    freopen("A.out","w",stdout);
    #endif // SKY
    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));
    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);
   // 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;
}

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