Submission #800520

#	Time	Username	Problem	Language	Result	Execution time	Memory
800520		Boas	Detecting Molecules (IOI16_molecules)	C++17	9 / 100	1 ms	304 KiB

molecules

#include "molecules.h"

using namespace std;
#include <bits/stdc++.h>

#define MAX_N 200001
#define ALL(x) x.begin(), x.end()
#define loop(x) for (int i = 0; i < (x); i++)
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;

vi find_subset(int l, int u, vi w)
{
    vii sortedW;
    loop(w.size())
    {
        if (w[i] > u)
            continue;
        sortedW.push_back({w[i], i});
    }
    sort(ALL(sortedW));
    vi used;
    bitset<MAX_N> usin;
    int totalW = 0;
    while (totalW < l)
    {
        bool added = false;
        for (int i = sortedW.size() - 1; i >= 0; i--)
        {
            if (usin[i])
                continue;
            const auto &[W, ix] = sortedW[i];
            if (totalW + W > u)
            {
                continue;
            }
            added = true;
            used.push_back(ix);
            usin[i] = true;
            totalW += W;
            sortedW.erase(sortedW.begin() + i);
        }
        if (!added)
            break;
    }
    if (totalW >= l)
        return used;
    if (sortedW.size() < 2)
        return {};
    const auto &[W, ix] = sortedW[0];
    used.push_back(ix);
    totalW += W;
    usin[0] = true;
    vi oldUsed(used);
    bitset<MAX_N> oldUsin(usin);
    int oldW = totalW;
    for (int i1 = 0; i1 < sortedW.size(); i1++)
    {
        if (used[i1])
            continue;
        ii p1 = sortedW[i1];
        for (int i2 : oldUsed)
        {
            ii p2 = sortedW[i2];
            used = oldUsed;
            used[find(ALL(used), p2.second) - used.begin()] = p1.second;
            totalW = oldW - p2.first + p1.first;
            if (totalW > u)
                continue;
            while (totalW < l)
            {
                bool added = false;
                for (int i = sortedW.size() - 1; i >= 0; i--)
                {
                    if (usin[i])
                        continue;
                    const auto &[W, ix] = sortedW[i];
                    if (totalW + W > u)
                    {
                        continue;
                    }
                    added = true;
                    used.push_back(ix);
                    usin[i] = true;
                    totalW += W;
                    sortedW.erase(sortedW.begin() + i);
                }
                if (!added)
                    break;
            }
            if (totalW >= l)
                return used;
        }
    }
    return {};
}

Compilation message (stderr)

molecules.cpp: In function 'vi find_subset(int, int, vi)':
molecules.cpp:8:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 | #define loop(x) for (int i = 0; i < (x); i++)
      |                                 ~~^~~~~
molecules.cpp:16:5: note: in expansion of macro 'loop'
   16 |     loop(w.size())
      |     ^~~~
molecules.cpp:58:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |     for (int i1 = 0; i1 < sortedW.size(); i1++)
      |                      ~~~^~~~~~~~~~~~~~~~

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