Submission #679719

#	Time	Username	Problem	Language	Result	Execution time	Memory
679719		sentheta	Detecting Molecules (IOI16_molecules)	C++17	9 / 100	1 ms	212 KiB

molecules

#include "molecules.h"
// author : sentheta aka vanwij
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cassert>
#include<random>
#include<chrono>
#include<cmath>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<stack>
#include<map>
#include<set>
using namespace std;

#define Int long long
#define V vector
#define pii pair<int,int>
#define ff first
#define ss second

#define rand() (uniform_int_distribution<int>(0,1<<30)(rng))
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

#define pow2(x) (1LL<<(x))
#define msb(x) (63-__builtin_clzll(x))
#define bitcnt(x) (__builtin_popcountll(x))

#define nl '\n'
#define _ << ' ' <<
#define all(x) (x).begin(), (x).end()
#define rep(i,a,b) for(int i = (int)(a); i < (int)(b); i++)
#define dbg(x) if(1) cout << "?" << #x << " : " << (x) << endl << flush;

const int N = 2e5+5;

Int n;
Int l, r;

Int a[N];
Int ord[N];

Int prf[N];

// take i elements, j of which are from suffix
Int f(int i,int j){
	Int ret = prf[i-1];
	if(j){
		ret -= prf[j-1];
		ret += prf[n-1];
		if(j!=n) ret -= prf[n-j-1];
	}
	return ret;
}

V<int> find_subset(int _l,int _r,V<int> _a){
	n = _a.size(); l=_l; r=_r;
	rep(i,0,n) a[i] = _a[i];


	rep(i,0,n) ord[i] = i;
	sort(ord,ord+n,[&](int i,int j){
		return a[i] < a[j];
	});
	prf[0] = a[ord[0]];
	rep(i,1,n){
		prf[i] = prf[i-1] + a[ord[i]];
	}

	for(Int cnt=1; cnt<=n; cnt++){
		Int suf = 0;
		for(Int J=1<<20; J; J/=2)
			if(suf+J<=cnt && f(cnt,suf+J)<=r) suf+=J;
		
		Int sum = f(cnt,suf);
		if(l<=sum && sum<=r){
			V<int> ans(cnt);
			rep(i,0,cnt) ans[i] = ord[i];
			rep(i,0,suf) ans[i] = ord[n-1-i];
			return ans;
		}
	}

	return {};
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 10
• Subtask 3: 0 / 12
• Subtask 4: 0 / 15
• Subtask 5: 0 / 23
• Subtask 6: 0 / 31