Submission #825548

#	Time	Username	Problem	Language	Result	Execution time	Memory
825548		Edu175	Counting Mushrooms (IOI20_mushrooms)	C++17	0 / 100	19 ms	352 KiB

mushrooms

#include "mushrooms.h"
#include <bits/stdc++.h>
#define pb push_back
#define fst first
#define snd second
#define fore(i,a,b) for(ll i=a,ioi=b;i<ioi;i++)
#define SZ(x) ((int)x.size())
#define ALL(x) x.begin(),x.end()
#define mset(a,v) memset((a),(v),sizeof(a))
#define imp(v) for(auto dfh:v)cout<<dfh<<" ";cout<<"\n"
using namespace std;
typedef long long ll;
typedef pair<ll,ll> ii;
const ll MAXN=2e4+5;

ll ask(vector<ll>a){
	vector<int>ai;
	for(auto i:a)ai.pb(i);
	return use_machine(ai);
}
map<ii,ll>did;
ll ran(ll l, ll r){ //[,]
	if(did.count({l,r}))return did[{l,r}];
	ll &res=did[{l,r}];
	if(l==r)return res=0;
	vector<ll>a;
	fore(i,l,r+1)a.pb(i);
	return res=ask(a);
}
int count_mushrooms(int n){
	ll res=0;
	ll p=0,k=ran(0,n-1)+1;
	ll c=0;
	while(k>1){
		//cout<<p<<" "<<k<<" "<<c<<": ";
		ll l=p,r=n-k,s=p;
		while(l<=r){
			ll m=(l+r)/2;
			if(ran(s,m)==0)l=m+1,s=m;
			else r=m-1;
		}
		if(!c)res+=l-p;
		//cout<<l<<"\n";
		p=l;
		c^=1;
		k--;
	}
	if(!c)res+=n-p;
	return res;
}

• Subtask 1: 0 / 100