제출 #967576

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
967576		12345678	Regions (IOI09_regions)	C++17	70 / 100	8080 ms	21844 KiB

regions

#include <bits/stdc++.h>

using namespace std;

const int nx=2e5+5, k=600, kx=25005;

int n, x, q, p, in[nx], out[nx], t, a, b, sz, res;
vector<int> d[nx], r[kx], vin[kx], vout[kx];

struct fenwick
{
    int d[nx];
    void update(int i, int vl) {while (i<nx) d[i]+=vl, i+=(i&-i);}
    int query(int i)
    {
        int res=0;
        while (i>0) res+=d[i], i-=(i&-i);
        return res;
    }
} f;

void dfs(int u)
{
    in[u]=++t;
    for (auto v:d[u]) dfs(v);
    out[u]=t;
}

int bruteforce(int a, int b)
{
    for (auto x:r[b]) f.update(in[x], 1);
    int res=0;
    for (auto x:r[a]) res+=f.query(out[x])-f.query(in[x]-1);
    for (auto x:r[b]) f.update(in[x], -1);
    return res;
}

int main()
{
    cin>>n>>sz>>q;
    cin>>x;
    r[x].push_back(1);
    for (int i=2; i<=n; i++) cin>>p>>x, d[p].push_back(i), r[x].push_back(i);
    dfs(1);
    for (int i=1; i<=sz; i++)
    {
        if (r[i].size()>=k)
        {
            vin[i].resize(kx);
            vout[i].resize(kx);
            for (int j=1; j<=sz; j++) if (i!=j) vin[i][j]=bruteforce(i, j), vout[i][j]=bruteforce(j, i);
        }
    }
    while (q--)
    {
        cin>>a>>b;
        if (r[a].size()>=k) res=vin[a][b];
        else if (r[b].size()>=k) res=vout[b][a];
        else res=bruteforce(a, b);
        cout<<res<<'\n';
        fflush(stdout);
    }
}

/*
6 3 4
1
1 2
1 3
2 3
2 3
5 1
*/

• Subtask 1: 15 / 15
• Subtask 2: 55 / 85