Submission #203331

#	Time	Username	Problem	Language	Result	Execution time	Memory
203331		wendy_virgo	Race (IOI11_race)	C++14	0 / 100	9 ms	5112 KiB

race

#include <bits/stdc++.h>

using namespace std;

#define taskname "IOI11_race"
#define forinc(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define fordec(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define foreach(i, x) for (auto &i : x)
#define ms(x, n) memset(x, n, sizeof(x))
#define sz(x) int((x).size())
#define all(x) (x).begin(), (x).end()
#define uni(x) (x).erase(unique(all(x)), (x).end())
#define fi first
#define se second
#define pb push_back
#define pf push_front

template<typename TH>
void _dbg(const char* sdbg, TH h)
{
	cerr << sdbg << " = " << h << "\n";
}

template<typename TH, typename... TA>
void _dbg(const char* sdbg, TH h, TA... t)
{
	while (*sdbg != ',') cerr << *sdbg++;
	cerr << " = " << h << ",";
	_dbg(sdbg + 1, t...);
}

#define db(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define chkpt cerr << "--- Checkpoint here ---\n";

const int N=2e5+5,INF=1e9;

int n,k,l[N];
vector<pair<int,int>> g[N];
int nEdge[1002][1002],root;
int64_t dist[1002][1002];

void DFS(int u,int fa,int d,int64_t sumW)
{
    nEdge[root][u]=d;
    dist[root][u]=sumW;
    foreach(p,g[u])
    {
        if(p.fi!=fa)
        {
            DFS(p.fi,u,d+1,sumW+l[p.se]);
        }
    }
}

void Calc(int u)
{
    root=u;
    DFS(u,-1,0,0);
}

int Sub2()
{
    forinc(i,0,n-1)
    {
        Calc(i);
    }
    int ans=INF;
    forinc(u,0,n-1)
    {
        forinc(v,u+1,n-1)
        {
            if(dist[u][v]==k)
            {
                ans=min(ans,nEdge[u][v]);
            }
        }
    }
    return (ans==INF?-1:ans);
}

int up[N][102],down1[N][102],down2[N][102];

void CalcDown(int u,int fa)
{
    down1[u][0]=0;
    foreach(p,g[u])
    {
        if(p.fi!=fa)
        {
            CalcDown(p.fi,u);
            forinc(i,0,k)
            {
                if(i-l[p.se]>=0&&down1[p.fi][i-l[p.se]]!=INF)
                {
                    int tmp=down1[p.fi][i-l[p.se]]+1;
                    if(tmp<=down1[u][i])
                    {
                        down2[u][i]=down1[u][i];
                        down1[u][i]=tmp;
                    }
                    else
                    {
                        down2[u][i]=min(down2[u][i],tmp);
                    }
                }
            }
        }
    }
}

void CalcUp(int u,int fa,int preW)
{
    up[u][0]=0;
    if(~fa)
    {
        forinc(i,0,k)
        {
            if(i-preW>=0)
            {
                if(up[fa][i-preW]!=INF)
                {
                    up[u][i]=min(up[u][i],up[fa][i-preW]+1);
                }
                if(down1[fa][i-preW]!=INF)
                {
                    if(down1[fa][i-preW]+preW==down1[u][i-preW])
                    {
                        if(down2[fa][i-preW]!=INF)
                        {
                            up[u][i]=min(up[u][i],down2[fa][i-preW]+1);
                        }
                    }
                    else
                    {
                        up[u][i]=min(up[u][i],down1[fa][i-preW]+1);
                    }
                }
            }
        }
    }
    foreach(p,g[u])
    {
        if(p.fi!=fa)
        {
            CalcUp(p.fi,u,l[p.se]);
        }
    }
}

int Sub3()
{
    forinc(i,0,n-1)
    {
        forinc(j,0,k)
        {
            up[i][j]=down1[i][j]=down2[i][j]=INF;
        }
    }
    CalcDown(0,-1);
    CalcUp(0,-1,0);
    int ans=INF;
    forinc(i,0,n-1)
    {
        ans=min(ans,min(up[i][k],down1[i][k]));
    }
    return (ans==INF?-1:ans);
}

int Solve()
{
    return Sub3();
}

int best_path(int N,int K,int H[][2],int L[])
{
    n=N;
    k=K;
    forinc(i,0,n-2)
    {
        g[H[i][0]].pb({H[i][1],i});
        g[H[i][1]].pb({H[i][0],i});
    }
    forinc(i,0,n-2)
    {
        l[i]=L[i];
    }
    return Solve();
}

//int main()
//{
//	ios_base::sync_with_stdio(0);
//	cin.tie(0);
//	#ifndef ONLINE_JUDGE
//	freopen(taskname".INP","r",stdin);
//	#endif // ONLINE_JUDGE
//	cin>>n>>k;
//	forinc(i,0,n-2)
//	{
//	    int u,v;
//	    cin>>u>>v;
//	    g[u].pb({v,i});
//	    g[v].pb({u,i});
//	}
//	forinc(i,0,n-2)
//	{
//	    cin>>l[i];
//	}
//	cout<<Solve();
//    return 0;
//}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57