Submission #430050

#	Time	Username	Problem	Language	Result	Execution time	Memory
430050		dreezy	Counting Mushrooms (IOI20_mushrooms)	C++17	0 / 100	4 ms	200 KiB

mushrooms

#include <bits/stdc++.h>
#include "mushrooms.h"
using namespace std;
#define pb push_back

int geta(int l, int r){
	if( l > r) return 0;
	if(l == r)
		return use_machine({0,l}) == 0;
	vector<int> inds;
	for(int i = l; i <=r; i++)inds.pb(i);
	int res = use_machine(inds);
	
	if(res == 0){
		if(use_machine({0, l})== 0)
			return r - l + 1;
		else
			return 0;
	}
	else if(res == r -l){
		if((r - l + 1)%2 == 0) return (r - l + 1)/2;
		else {
			if(use_machine({0,l}) == 0){
				return (r - l + 1)/2 + 1;
			}
			else
				return (r - l + 1)/2;
		}
	}
	else if(res == 1){
		int lo = l;
		int hi = r;
		int target = !use_machine({0, lo});
		
		while(lo!= hi){
			int mi = (lo + hi)/2;
				if( use_machine({0,mi}) == target){
					hi = mi;
				}
				else{
					lo = mi + 1;
				}
		}
		
		if(target == 1){//we were looking for the first B
			return lo - 1 - l;
		}
		else{//we were looking for the first A
			return r - lo  + 1;
		}
	}
	int mid = (l + r)/2;
	return geta( l, mid) + geta(mid + 1, r);
}
int count_mushrooms(int n) {
	
	return 1 + geta(1, n -1);
}
/************************/

• Subtask 1: 0 / 100