Submission #73060

#	Time	Username	Problem	Language	Result	Execution time	Memory
73060		dmfr	Detecting Molecules (IOI16_molecules)	C++11	10 / 100	4 ms	748 KiB

molecules

#include "molecules.h"

#include <map>
#include <deque>
#include <vector>

#include <algorithm>
#include <numeric>

//#include <iostream>

using namespace std;

typedef pair<int,int> pii;

/*
4 15 17
6 8 8 7
=>2
=>2 3

4 15 17
4 6 6 5
=>3
=> 1 3 0

4 14 15
5 5 6 6
=>0

4 10 20
15 17 16 18
=>1
=>3

4 0 0
0 0 0 0
=>1
=>3

*/

vector<int> find_subset(int l, int u, vector<int> w) {
    const int& N = w.size();
    const int& UpperBound = u;
    const int& LowerBound = l;

    vector<pii> wVtr(N);
    for(int i = 0; i < N; ++i)
        wVtr[i] = pii(w[i], i);

    sort(wVtr.begin(), wVtr.end());
    while(!wVtr.empty() && wVtr.front().first > UpperBound) wVtr.pop_back();
    if(wVtr.empty())                      return vector<int>(0);
    if(l <= wVtr.back().first && wVtr.back().first <= UpperBound) return vector<int>(1,wVtr.back().second);
    if(accumulate(w.begin(),w.end(),0) < l) return vector<int>(0);
    reverse(wVtr.begin(),wVtr.end());

//    cout << "w:";
//    for(const auto& i:w) cout << i << " ";
//    cout << endl;

    map<int,deque<int>> PossibleNumbers_left;{
        PossibleNumbers_left[0] = deque<int>();
        deque<pair<int,deque<int>>> ToInsert;
        for(int i = 0; i < N/2; ++i){
            const pii& w_i = wVtr[i];
            for(const auto& n:PossibleNumbers_left)
                if(n.first+w_i.first <= UpperBound){
                    ToInsert.push_back(n);
                    ToInsert.back().first += w_i.first;
                    ToInsert.back().second.push_back(w_i.second);
                }
            while(!ToInsert.empty()){
                PossibleNumbers_left[ToInsert.back().first] = ToInsert.back().second;
                ToInsert.pop_back();
            }
            const auto& W = PossibleNumbers_left.rbegin();
            if(LowerBound <= W->first && W->first <= UpperBound)
                return vector<int>(W->second.begin(),W->second.end());

        }
//        cout << "PossibleNumbers_left:" << endl;
//        for(const auto& n:PossibleNumbers_left){
//            cout << n.first << ": ";
//            for(const auto& m:n.second) cout << m << " ";
//            cout << endl;
//        }cout << endl;
    }
    map<int,deque<int>> PossibleNumbers_right;{
        PossibleNumbers_right[0] = deque<int>();
        deque<pair<int,deque<int>>> ToInsert;
        for(int i = N/2; i < N; ++i){
            const pii& w_i = wVtr[i];
            for(const auto& n:PossibleNumbers_right)
                if(n.first+w_i.first <= UpperBound){
                    ToInsert.push_back(n);
                    ToInsert.back().first += w_i.first;
                    ToInsert.back().second.push_back(w_i.second);
                }
            while(!ToInsert.empty()){
                PossibleNumbers_right[ToInsert.back().first] = ToInsert.back().second;
                ToInsert.pop_back();
            }
            const auto& W = PossibleNumbers_right.rbegin();
            if(LowerBound <= W->first && W->first <= UpperBound)
                return vector<int>(W->second.begin(),W->second.end());

        }
//        cout << "PossibleNumbers_right:" << endl;
//        for(const auto& n:PossibleNumbers_right){
//            cout << n.first << ": ";
//            for(const auto& m:n.second) cout << m << " ";
//            cout << endl;
//        }cout << endl;
    }

    for(const auto& p:PossibleNumbers_left){
        int ToFind = LowerBound - p.first;
        auto it = PossibleNumbers_right.lower_bound(ToFind);
        if(LowerBound <= p.first + it->first && p.first + it->first <= UpperBound){
            vector<int> ret(p.second.begin(), p.second.end());
            ret.insert(ret.end(), it->second.begin(), it->second.end());
            return ret;
        }
    }

    return vector<int>(0);
}

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