Submission #1112564

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112564		FucKanh	Regions (IOI09_regions)	C++14	45 / 100	8077 ms	26184 KiB

regions

#include<bits/stdc++.h>
#define ll long long
#define int ll
#define pii pair<int,int>

using namespace std;

const int maxn = 2e5 + 2;

int tin[maxn], tout[maxn],t;
vector<int> re[maxn],a[maxn];

void dfs(int u) {
    tin[u] = ++t;
    for (int v : a[u]){
        dfs(v);
    }
    tout[u] = t;
}

void solve() {
    int n,r,q; cin >> n >> r >> q;
    int wat; cin >> wat;
    re[wat].push_back(1);
    int block = sqrt(n);
    for (int i = 2; i <= n; i++) {
        int x,y; cin >> x >> y;
        a[x].push_back(i);
        re[y].push_back(i);
    }
    dfs(1);
    for (int i = 1; i <= q; i++) {
        int x,y; cin >> x >> y;
        int ans = 0;
        for (int u : re[x]) {
            for (int v : re[y]) {
                ans += tin[u] <= tin[v] && tout[u] >= tout[v];
            }
        }
        cout << ans << endl;
    }
}

signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    solve();
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'void solve()':
regions.cpp:25:9: warning: unused variable 'block' [-Wunused-variable]
   25 |     int block = sqrt(n);
      |         ^~~~~

• Subtask 1: 15 / 15
• Subtask 2: 30 / 85