Submission #138370

#	Time	Username	Problem	Language	Result	Execution time	Memory
138370		arthurconmy	Detecting Molecules (IOI16_molecules)	C++14	100 / 100	70 ms	10356 KiB

molecules

#include <bits/stdc++.h>
#ifndef ARTHUR_LOCAL
	#include "molecules.h"
#endif
using namespace std;
using ll = long long;

vector<int> find_subset(int u, int d, vector<int> W_raw) 
{
	int n = W_raw.size();
	int l = ll(u);
	int r = ll(d);

    vector<pair<ll,int>> W;

    for(int i=0; i<n; i++)
    {
    	W.push_back(make_pair(ll(W_raw[i]),i));
    }

    sort(W.begin(),W.end());

    ll cur1=0;
    ll cur2=0;
    vector<int> v1;
    vector<int> v2;
    bool works=0;

    for(int i=1; i<=n; i++)
    {
    	cur1 += W[i-1].first;
    	v1.push_back(W[i-1].second);
    	
    	cur2 += W[n-i].first;
    	v2.push_back(W[n-i].second);

    	if(cur1 >= l && cur1 <= r)
    	{
    		// return cur1 things
    		return v1;
    	}

    	if(cur2 >= l && cur2 <= r)
    	{
    		return v2;
    	}

    	if(cur1 < l && cur2 > r) // LOOKS DODGY, PROBABLY IS RIGHT
    	{
    		works=1;
    		break;
    	}
    }

    if(!works) return {};

    // definitely at this point

    for(int i=0; i<v1.size(); i++)
    {
    	cur2 -= ll(W_raw[v2[v1.size()-i-1]]);
    	cur2 += ll(W_raw[v1[i]]);				// after this update, cur2 decreases by at most

    	v2[v1.size()-i-1]=v1[i];

    	if(cur2 <= r && cur2 >= l) return v2;
    }

    return {};
}

#ifdef ARTHUR_LOCAL
	int main()
	{
		vector<int> V = find_subset(50,51,{25,26});
		cout << V.size() << endl;
		for(auto v:V) cout << v << " ";
	}
#endif

Compilation message (stderr)

molecules.cpp: In function 'std::vector<int> find_subset(int, int, std::vector<int>)':
molecules.cpp:59:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v1.size(); i++)
                  ~^~~~~~~~~~

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