Submission #1113541

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113541		epicci23	The Big Prize (IOI17_prize)	C++17	90 / 100	180 ms	2400 KiB

prize

#include "bits/stdc++.h"
#include "prize.h"
//#define int long long
#define all(v) v.begin() , v.end()
#define sz(a) (int)a.size()
using namespace std;
 
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

inline int rand(int l,int r){
  return l + rng() % (r-l+1);
}


const int BL = 500;

int suf = -1;
vector<int> Cache={-1,-1};
map<int,vector<int>> dp;
 
vector<int> Ask(int i){
  if( dp.count(i) ) return dp[i];
  return dp[i] = ask(i);
}
 
int ask_all(int l,int r){
  for(int i = l; i <= r; i++){
    vector<int> x = Ask(i);
    if(x[0] + x[1] == 0) return i;
    if(x[1] == suf) Cache = x;
    else suf--;
  }
  return -23;
}
 
int Learn(int l,int r){
  if(l>r) return -1;
  if(l==r){
    auto u = Ask(l);
    if(u[0] + u[1] == 0) return l;
    if(u[1] == suf) Cache=u;
    else suf--;
    return -1;
  }

  auto X = Ask(r);
  if(X[0] + X[1] == 0) return r;
  if(X[1] == suf) return -1;

  if(l+BL+1<r){
    auto u = Ask(l + BL);
    if(u[0]+u[1]==0) return l+BL;
    if(u[1] == suf) return Learn(l+BL+1,r-1);
    int hm = Learn(l,l+BL-1);
    if(hm != -1) return hm;
    if(u[1] == suf) Cache = u;
    else suf--;
    if(X[1] == suf - ( Cache[0] + Cache[1] > X[0] + X[1] ) ) return -1;
    int hm2 = Learn(l+BL+1,r-1);
    if(hm2 != -1) return hm2;
    if(X[1] == suf) Cache = X;
    else suf--;
    return -1;
  }

  int mid = (l+r) / 2;
  auto u = Ask(mid);
  if(u[0] + u[1] == 0) return mid;
  if(u[1] == suf) return Learn(mid + 1,r - 1);
  int lf = Learn(l,mid - 1);
  if(lf != -1) return lf;
  if(u[1]==suf) Cache = u;
  else suf--; 
  if(X[1] == suf - ( Cache[0] + Cache[1] > X[0] + X[1] ) ) return -1;
  int hm = Learn( mid + 1, r - 1 );
  if(hm != -1) return hm;
  if(X[1] == suf) Cache = X;
  else suf--;
  return -1;
}
 
int find_best(int n){
  if(n <= 1000) return ask_all(0, n - 1);
  int art = 0;
  for(int i = 0; i <= 500; i++){
  	if(art == 5) return Learn(i, n - 1);
    vector<int> x = Ask(i);
    if(x[0] + x[1] == 0) return i;
    if(x[0] + x[1] > Cache[0] + Cache[1]) art++;
    if(x[0] + x[1] >= Cache[0] + Cache[1]){
      Cache = x;
      suf = Cache[1];
    }
    else suf--;
  }
  return Learn(501, n - 1 );
}

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80