Submission #1013189

#	Time	Username	Problem	Language	Result	Execution time	Memory
1013189		jcelin	The Big Prize (IOI17_prize)	C++14	100 / 100	38 ms	2260 KiB

prize

#include<bits/stdc++.h>
#include "prize.h"
using namespace std;

typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long long ll;
#define X first
#define Y second
#define PB push_back
#define PPB pop_back
#define all(x) (x).begin(), (x).end() 

const int MAXN = 2e5 + 7;
mt19937 rng(time(0));
vi mog;
int svi;
ii q[MAXN];

void as(int x){
	if(q[x].X == -1){
		vi ret = ask(x);
		q[x] = {ret[0], ret[1]};
	}
}

int l(int x){
	as(x);
	return q[x].X;
}

int r(int x){
	as(x);
	return q[x].Y;
}

void rek(int lo, int hi){
	if(lo > hi) return;
	
	if(l(lo) + r(lo) < svi){
		mog.PB(lo);
		rek(lo + 1, hi);
		return;
	}
	
	if(l(hi) + r(hi) < svi){
		mog.PB(hi);
		rek(lo, hi - 1);
		return;
	}
	
	if(l(lo) == l(hi) or lo + 1 == hi) return;
	int mid = (lo + hi) / 2;
	rek(lo, mid);
	rek(mid, hi);
}

int find_best(int n){
	fill(q, q + n, (ii){-1, -1});
	
	for(int i=0; i<100; i++){
		int x = rng() % n;
		svi = max(svi, l(x) + r(x));
	}
	rek(0, n-1);
	
	for(auto &x : mog) if(l(x) + r(x) == 0) return x;
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:69:1: warning: control reaches end of non-void function [-Wreturn-type]
   69 | }
      | ^

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