Submission #316227

#	Time	Username	Problem	Language	Result	Execution time	Memory
316227		MrDomino	The Big Prize (IOI17_prize)	C++14	0 / 100	118 ms	10216 KiB

prize

#include <bits/stdc++.h>
#include "prize.h"

using namespace std;

mt19937 rng((long long) (new char));
const int N = 200000 + 7;
vector<int> ret[N];
set<int> s;
int mx;
int sol;

vector<int> get(int i) {
  if (ret[i].empty()) {
    ret[i] = ask(i);
    if (ret[i][0] == 0 && ret[i][1] == 0) {
      sol = i;
    }
  }
  return ret[i];
}

bool is(int x) {
  return get(x)[0] + get(x)[1] == mx;
}

int rep(int l, int r) {
  if (l > r) {
    return 0;
  }
  auto it = s.lower_bound(r);
  if (it != s.end()) {
    auto it2 = s.lower_bound(l + 1);
    if (it2 != s.begin()) {
      it2--;
      int f = *it2;
      int s = *it;
      if (get(f)[0] == get(s)[0]) {
        return 0;
      }
    }
  }
  int m = (l + r) / 2;
  if (get(m)[0] == 0 && get(m)[1] == 0) {
    return m;
  }
  int x = rep(l, m - 1);
  if (x == 0) {
    x = rep(m + 1, r);
  }
  return x;
}

int find_best(int n) {
  sol = -1;
  vector<int> ord(n);
  for (int i = 0; i < n; i++) {
    ord[i] = i;
  }
  shuffle(ord.begin(), ord.end(), rng);
  while ((int) ord.size() > 100) {
    ord.pop_back();
  }
  mx = 0;
  for (auto &x : ord) {
    mx = max(mx, get(x)[0] + get(x)[1]);
  }
  for (auto &x : ord) {
    if (is(x)) {
      s.insert(x);
    }
  }
  if (sol != -1) {
    return sol;
  }
  rep(0, n - 1);
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:56:20: warning: control reaches end of non-void function [-Wreturn-type]
   56 |   vector<int> ord(n);
      |                    ^

• Subtask 1: 0 / 20
• Subtask 2: 0 / 80