Submission #231511

#	Time	Username	Problem	Language	Result	Execution time	Memory
231511		border	Ball Machine (BOI13_ballmachine)	C++14	16.11 / 100	1082 ms	30644 KiB

ballmachine

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
 
using namespace std;
using namespace __gnu_pbds;
 
#define debug(s) cerr << #s << " = " << s << '\n'
#define all(v) (v).begin(), (v).end()
#define mem(a,val) memset(a, val, sizeof a)
 
#define ff first
#define ss second
typedef long long ll;
 
typedef tree<pair<int, int>,null_type,less<pair<int, int>>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

const int N = 100010;

int n, q, ptr, root;
int T[N], P[N][24], L[N], rev[N], val[N];
vector<int> adj[N];
ordered_set s;

void dfs(int from, int u, int dep) {
  T[u] = from;
  L[u] = dep;
  for (auto v: adj[u]){
    if (v == from) continue;
    dfs(u, v, dep + 1);
  }
  rev[ptr] = u;
  val[u] = ptr;
  s.insert({ptr++, u});
}

void init() {
  int i, j;
  for (i = 1; i <= n; i++)
    for (j = 0; 1 << j < n; j++)
      P[i][j] = -1;
  for (i = 1; i <= n; i++)
    P[i][0] = T[i];
  for (j = 1; 1 << j < n; j++)
    for (i = 1; i <= n; i++)
      if (P[i][j - 1] != -1)
        P[i][j] = P[P[i][j - 1]][j - 1];
}

int klevpar(int u, int k) {
  int log, i;
  for (log = 1; 1 << log <= L[u]; log++);
  log--;
  for (i = log; i >= 0; i--)
    if (L[u] - (1 << i) >= k)
      u = P[u][i];
  
  return u;
}

int main() {
  scanf("%d %d", &n, &q);
  for (int i = 1; i <= n; ++i) {
    int x;
    scanf("%d", &x);
    if (x == 0) root = i;
    adj[x].push_back(i);
  }
  for (int i = 1; i <= n; ++i) sort(all(adj[i]));
  dfs(-1, root, 0);
  init();
  while (q--) {
    int ty, v;
    scanf("%d %d", &ty, &v);
    if (ty == 1) {
      int ret = (*s.find_by_order(v - 1)).ss;
      printf("%d\n", ret);
      while (v--) s.erase(*s.find_by_order(0));
    }
    else {
      int ret = 0;
      int lo = 0, hi = L[v], u = v;
      while (lo <= hi) {
        int mid = (lo + hi) >> 1;
        int midu = klevpar(v, mid);
        if (s.find({val[midu], midu}) == s.end()) {
          u = midu;
          hi = mid - 1;
        }
        else lo = mid + 1;
      }
      s.insert({val[u], u});
      ret = L[v] - L[u];
      printf("%d\n", ret);
    }
  }
}

Compilation message (stderr)

ballmachine.cpp: In function 'int main()':
ballmachine.cpp:62:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &n, &q);
   ~~~~~^~~~~~~~~~~~~~~~~
ballmachine.cpp:65:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &x);
     ~~~~~^~~~~~~~~~
ballmachine.cpp:74:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &ty, &v);
     ~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 25
• Subtask 2: 6.428571428571429 / 30
• Subtask 3: 8.571428571428571 / 40
• Subtask 4: 1.1111111111111112 / 5