fork download
copy 
  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. typedef long long ll;
  5. #define nl '\n'
  6. #define ff first
  7. #define ss second
  8. #define pb push_back
  9. #define sik(x) {cout << x << nl; return;}
  10. const ll maxn = 2e5+20, mod = 1e9 + 7, inf = 1e10;
  11. typedef pair<ll,ll> pii;
  12.  
  13. ll n, q;
  14. vector<ll> g[maxn], ans;
  15. set<pii> qr[maxn];
  16. vector<ll> pth;
  17. bool vis[maxn];
  18.  
  19. void dfs(ll v) {
  20.   vis[v] = 1;
  21.   pth.pb(v);
  22.   for (auto [k, i] : qr[v]) {
  23.     if (pth.size() - k - 1 >= 0) ans[i] = pth[pth.size() - k - 1];
  24.     else ans[i] = -1;
  25.   }
  26.   for (auto u : g[v]) {
  27.     if (!vis[u]) dfs(u);
  28.   }
  29.   pth.pop_back();
  30. }
  31.  
  32. int32_t main() {
  33.   //cout << fixed << setprecision(5);
  34.   cin.tie(0)->sync_with_stdio(0); 
  35.   cin >> n >> q, ans.assign(q, {});
  36.   for (int u = 2, v ; u <= n ; u ++) {
  37.     cin >> v;
  38.     g[u].pb(v);
  39.     g[v].pb(u);
  40.   }
  41.   for (int i = 0 ; i < q ; i ++) {
  42.     ll x, k; cin >> x >> k;
  43.     qr[x].insert({k, i});
  44.   }
  45.   dfs(1);
  46.  
  47.   for (auto i : ans) cout << i << nl;
  48. }
  49.  
Success #stdin #stdout 0.01s 17568KB
comments (?)
stdin
copy 
5 1
1 2 2 3
2 2
stdout
copy 
33
https://ideone.com/QZqua6
language:
C++ (gcc 8.3)
created:
12 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!