Submission #72822

#	Time	Username	Problem	Language	Result	Execution time	Memory
72822		funcsr	The Big Prize (IOI17_prize)	C++17	20 / 100	71 ms	3792 KiB

prize

#include "prize.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cassert>
#include <random>
using namespace std;
#define rep(i,n)for (int i=0; i<(n); i++)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define _1 first
#define _2 second
#define INF 1145141919
typedef pair<int, int> P;
mt19937 mt_rand(114514);
int mp = 0;
P cache[200000];
int Q=0;
P query(int x) {
  if (cache[x] != P(-1, -1)) return cache[x];
  Q++;
  assert(Q<=10000);
  //if(Q%100==0)cout<<"Q="<<Q<<"\n";
  vector<int> ret = ask(x);
  return cache[x] = {ret[0], ret[1]};
}

int solve(int l, int r, int num, int left) {
  if (num <= 0) return -1;
  //cout<<"solve("<<l<<","<<r<<", num="<<num<<")\n";
  for (int mid=(l+r)/2+1; mid<=r; mid++) {
    P ret = query(mid);
    if (ret._1+ret._2 == 0) return mid;
    if (ret._1+ret._2 != mp) continue;
    if (mid > l) {
      int o = solve(l, mid-1, ret._1-left, left);
      if (o != -1) return o;
    }
    if (mid < r) {
      int o = solve(mid+1, r, num-(ret._1-left), ret._1);
      if (o != -1) return o;
    }
    return -1;
  }
  for (int mid=(l+r)/2; mid>=l; mid--) {
    P ret = query(mid);
    if (ret._1+ret._2 == 0) return mid;
    if (ret._1+ret._2 != mp) continue;
    if (mid > l) {
      int o = solve(l, mid-1, ret._1-left, left);
      if (o != -1) return o;
    }
    if (mid < r) {
      int o = solve(mid+1, r, num-(ret._1-left), ret._1);
      if (o != -1) return o;
    }
    return -1;
  }
  return -1;
}

int find_best(int N) {
  rep(i, N) cache[i] = P(-1, -1);
  rep(i, 30) {
    P ret = query(mt_rand()%N);
    mp = max(mp, ret._1+ret._2);
  }
  //cout<<"mp="<<mp<<"\n";
  assert(mp < 500);
  int r = solve(0, N-1, mp, 0);
  assert(r != -1);
  return r;
}

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