Submission #802036

#	Time	Username	Problem	Language	Result	Execution time	Memory
802036		mrwang	Regions (IOI09_regions)	C++14	50 / 100	2403 ms	45556 KiB

regions

#include<bits/stdc++.h>
#define TASKNAME "codeforce"
#define pb push_back
#define pli pair<int,int>
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;
using ll=long long;
const ll maxN=2e5+10;
const ll inf=1e18;
const ll mod=1e9+7;
ll in[maxN],out[maxN],tg=0,h[maxN],cnt[maxN],ct[maxN];
ll dem1[450][25000],dem2[450][25000];
vector<ll>g[maxN];
void DFS(ll u)
{
    in[u]=++tg;
    for(int v:g[u])
    {
        DFS(v);
    }
    out[u]=tg;
}
ll k[maxN];
void dfs(ll u,ll c,ll i)
{
    cnt[u]=k[u]==c;
    for(int v:g[u])
    {
        h[v]=h[u]+(k[v]==c);
        dfs(v,c,i);
        cnt[u]+=cnt[v];
    }
    dem1[i][k[u]]+=cnt[u];
    dem2[i][k[u]]+=h[u];
}
ll n,r,q;
vector<ll>vv[25000],vec[25000];
ll pp[maxN];
void solve()
{
    cin >> n >> r >> q;
    for(int i=1;i<=n;i++)
    {

        if(i!=1)
        {
            ll p;
            cin >> p;
            g[p].pb(i);
        }
        cin >> k[i];
        ct[k[i]]++;
        vv[k[i]].pb(i);
    }

    ll sz=0;
    DFS(1);
    for(int i=1;i<=r;i++)
    {
        if(ct[i]*ct[i]>n)
        {
            ++sz;
            pp[i]=sz;
            dfs(1,i,sz);
        }
    }
    for(int i=1;i<=n;i++)
    {
        vec[k[i]].pb(in[i]);
    }
    for(int i=1;i<=r;i++) sort(vec[i].begin(),vec[i].end());
    for(int i=1;i<=q;i++)
    {
        ll x,y;
        cin >> x >> y;
        if(ct[x]*ct[x]>n)
        {
            cout << dem2[pp[x]][y]<<endl;
        }
        else if(ct[y]*ct[y]>n)
        {
            cout << dem1[pp[y]][x]<<endl;
        }
        else
        {
            ll ans=0;
            for(auto zz:vv[x])
            {
                ans+=upper_bound(vec[y].begin(),vec[y].end(),out[zz])-lower_bound(vec[y].begin(),vec[y].end(),in[zz]);
                
            }
            cout << ans<<endl;
        }
    }
}
int main()
{
    fastio
    //freopen(TASKNAME".INP","r",stdin);
    //freopen(TASKNAME".OUT","w",stdout);
    solve();
}

• Subtask 1: 15 / 15
• Subtask 2: 35 / 85