Submission #552938

#	Time	Username	Problem	Language	Result	Execution time	Memory
552938		beedle	Race (IOI11_race)	C++17	43 / 100	3060 ms	122356 KiB

race

#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <set>
#include <iterator>
#include <stack>
#include <map>
#include <math.h>
#include <bitset>
#include <deque>
#include <string>
#include <tuple>
#include <queue>
#include <numeric>
#include <unordered_set>
#include <unordered_map>
#define pi 3.141592653589793238
#define ll long long
#define ld long double
#define rep(i, a, b) for (long long i = a; i <= b; i++)
#define mod 998244353ll
#define INF 1000000000000000000
#define pb push_back
#define ff first
#define ss second
#define endl '\n'
#define all(x) (x).begin (), (x).end ()
#define sz(x) (ll) (x).size ()
#define reunique(v) v.resize(std::unique(v.begin(), v.end()) - v.begin())
#define rank rnk
#define log lg
#define fast                                                                  \
    ios_base::sync_with_stdio (false);                                        \
    cin.tie (NULL);                                                           \
    cout.tie (NULL)
 
using namespace std;
 
void setup(ll v, ll p, ll width[], vector <pair<ll ,ll >> adj[])
{
    width[v]=1;
    for(auto u:adj[v])
    if(u.ff!=p)
    {
        setup(u.ff,v,width,adj);
        width[v]+=width[u.ff];
    }
}
 
ll traverse(ll n, ll v, ll p, ll width[], vector <pair<ll ,ll >> adj[])
{
    ll outlier=-1;
    for(auto u:adj[v])
    if(u.ff!=p)
    if(width[u.ff]>n/2)
    outlier=u.ff;
 
    if(outlier==-1)
    return v;
    else 
    return traverse(n,outlier,v,width,adj);
}
 
void dfs(ll v, ll p, ll k, ll &ans, vector <ll>  &mydist, map <ll ,ll > &minlen, map <ll ,ll > &minlenothers, vector <pair<ll ,ll >> adj[], ll depth, vector <ll>  &ch)
{
    if(mydist[v]<=k)
    {
        ll d=mydist[v];

        if(minlen[d]==0)
        minlen[d]=mod;

        minlen[d]=min(minlen[d],depth);
 
        if(d==k)
        ans=min(ans,minlen[d]);
 
        if(minlenothers[k-d]!=0)
        ans=min(ans,depth+minlenothers[k-d]);
 
        ch.push_back(d);
    }
 
    for(auto u:adj[v])
    if(u.ff!=p)
    {
        mydist[u.ff]=mydist[v]+u.ss;
        dfs(u.ff,v,k,ans,mydist,minlen,minlenothers,adj, depth+1, ch);
    }
}
 
void find_children(ll v, ll p, vector <ll>  &ch, vector <pair<ll ,ll >> adj[])
{
    ch.push_back(v);
    for(auto u:adj[v])
    if(u.ff!=p)
    find_children(u.ff,v,ch,adj);
}
 
ll solve(ll n, ll k, vector <pair<ll ,ll >> adj[])
{
    if(n==1)
    return mod;
 
    ll width[n+1];
    setup(1,-1,width, adj);
 
    ll v=traverse(n, 1,-1,width,adj);
 
    // cout<<"SETUP DONE: "<<v<<endl;
 
    map <ll ,ll > minlenothers;
    vector <ll>  mydist(n+1,mod);
    map <ll ,ll > minlen;
    ll ans=mod;
    vector <ll>  ch;
 
    for(auto u:adj[v])
    {
        mydist[u.ff]=u.ss;
        dfs(u.ff,v,k,ans,mydist,minlen,minlenothers,adj,1,ch);
 
        for(auto x:ch)
        {
            if(minlenothers[x]==0) minlenothers[x]=mod;
            minlenothers[x]=min(minlenothers[x],minlen[x]);
            minlen[x]=mod;
        }
 
        ch.clear();
    }
 
    // cout<<"ANS : "<<ans<<endl;
 
    for(auto u:adj[v])
    {
        find_children(u.ff,v,ch,adj);
 
        sort(all(ch));
        ll s=sz(ch);
        vector <ll>  m(n+1);
        rep(i,0,s-1)
        m[ch[i]]=i+1;
 
        vector <pair<ll ,ll >> nadj[s+1];
 
        rep(i,0,s-1)
        {
            ll vt=ch[i];
            for(auto u:adj[vt])
            if(u.ff!=v)
            {
                nadj[m[vt]].pb({m[u.ff],u.ss});
            }
        }
 
        ch.clear();
 
        // cout<<"IN "<<n<<endl;
        // cout<<s<<" "<<k<<endl;
        // rep(i,1,s)
        // {
        //     cout<<i<<" -> ";
        //     for(auto x:nadj[i])
        //     {
        //         cout<<x.ff<<","<<x.ss<<"  ";
        //     }
        //     cout<<endl;
        // }
        ans=min(ans,solve(s,k,nadj));
    }
 
    return ans;
}
 
int best_path(int  n, int  k, int  h[][2], int  l[])
{
    vector <pair<ll ,ll >> adj[n+1];
    rep(i,0,n-2)
    {
        adj[h[i][0]+1].pb({h[i][1]+1,l[i]});
        adj[h[i][1]+1].pb({h[i][0]+1,l[i]});
    }
 
    ll x=solve(n,k,adj);
    return (x==mod?-1:x);
}

// signed main()
// {
//     fast;

//     freopen("milkorder.in","r",stdin);
//     // freopen("milkorder.out","w",stdout);

//     ll n,k;
//     cin>>n>>k;

//     ll h[n-1][2];
//     ll l[n-1];

//     rep(i,0,n-2)
//     {
//         cin>>h[i][0]>>h[i][1]>>l[i];
//     }

//     cout<<best_path(n,k,h,l);

//     return 0;
// }

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