Submission #571068

#	Time	Username	Problem	Language	Result	Execution time	Memory
571068		web	Detecting Molecules (IOI16_molecules)	C++17	0 / 100	1 ms	296 KiB

molecules

#include <iostream>
#include "molecules.h"
#include <algorithm>
using namespace std;

vector<vector<int>> dp; 
void knapsack(vector<int>& weights, int u)
{
    for(int i = 0; i<weights.size(); ++i)
    {
        for(int  weight = 0; weight <= u; ++weight)
        {
            if(weight < weights[i])
            {
                dp[i+1][weight] = dp[i][weight];
            }
            else
            {
                if(dp[i][weight] >= dp[i][weight - weights[i]]+ weights[i])
                {
                    dp[i+1][weight] = dp[i][weight];
                }
                else
                {
                    dp[i+1][weight] = dp[i][weight-weights[i]] + weights[i];
                }
            }
        }
    }
    
}


std::vector<int> find_subset(int l, int u, std::vector<int> w) 
{
    vector<pair<int,int>> wP(w.size());
    for(int i = 0; i<w.size(); ++i)
    {
        wP[i] = {w[i], i};
    }
    sort(wP.begin(), wP.end());
    //construct prefix
    auto itStart = wP.begin();
    auto itPrefEnd = wP.begin();
    auto itSuffixStart = wP.end();
    int sum = 0;
    while(sum <= u && itPrefEnd != wP.end())
    {
        sum += (*itPrefEnd).first;
        itPrefEnd++;
    }

    if(sum > u)
    {
        itPrefEnd--;
        sum-= (*itPrefEnd).first;
    }
    //for(auto n:w)
      //  cout<<n<<" ";
    //cout<<endl;
    //cout<<"sum: "<<sum<<endl;
  //  cout<<"pos itstart: "<<itStart-wP.begin()<<endl;
    //cout<<"pos itPrefEnd: "<<itPrefEnd-wP.begin()<<endl;
    while(sum < l && itPrefEnd != itSuffixStart)
    {
        
        sum -= (*itStart).first;
        itStart++;
        itSuffixStart--;
        sum += (*itSuffixStart).first;
        
      //  cout<<"new sum " << sum<<endl;
    }
    if(sum >= l && sum <= u)
    {
        vector<int> retVal;
        while(itStart != itPrefEnd)
            {retVal.push_back((*itStart).second+1); itStart++;}
        while(itSuffixStart != wP.end())
        {
            retVal.push_back((*itSuffixStart).second +1);
            itSuffixStart++;
        }
        return retVal;
    }
    else
        return vector<int>(0);



}

Compilation message (stderr)

molecules.cpp: In function 'void knapsack(std::vector<int>&, int)':
molecules.cpp:9:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     for(int i = 0; i<weights.size(); ++i)
      |                    ~^~~~~~~~~~~~~~~
molecules.cpp: In function 'std::vector<int> find_subset(int, int, std::vector<int>)':
molecules.cpp:37:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |     for(int i = 0; i<w.size(); ++i)
      |                    ~^~~~~~~~~

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