Submission #496711

#	Time	Username	Problem	Language	Result	Execution time	Memory
496711		Dan4Life	Regions (IOI09_regions)	C++17	70 / 100	8066 ms	25284 KiB

regions

#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5+10;
int n,r,q,cnt=1, a[maxn], st[maxn], en[maxn], B[maxn];
vector<int> adj[maxn], v[25001];
void dfs(int s, int p = -1)
{
    st[s] = cnt++;
    for(auto u : adj[s])
        if(u!=p) dfs(u,s);
    en[s] = cnt-1;
}

int32_t main()
{
    cin >> n >> r >> q >> a[1];
    for(int i = 2; i <= n; i++)
    {
        int x; cin >> x >> a[i];
        adj[x].push_back(i);
    }
    dfs(1); for(int i = 1; i <= n; i++) B[st[i]]=i;
    for(int i = 1; i <= n; i++) v[a[B[i]]].push_back(st[B[i]]);
    while(q--)
    {
        int a, b, ans = 0; cin >> a >> b;
        for(auto u : v[a]){
            int l = st[B[u]], r = en[B[u]];
            auto itr = upper_bound(v[b].begin(), v[b].end(), r)-v[b].begin();
            auto itr2 = upper_bound(v[b].begin(), v[b].end(), l)-v[b].begin();
            if(itr) itr--, ans+=max((int)(itr-itr2)+1, 0);
        }
        cout << ans << endl;
    }
}

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