Submission #651873

#	Time	Username	Problem	Language	Result	Execution time	Memory
651873		alvinpiter	Detecting Molecules (IOI16_molecules)	C++17	100 / 100	56 ms	8608 KiB

molecules

#include "molecules.h"
#include<bits/stdc++.h>
using namespace std;
#define LL long long int

std::vector<int> find_subset(int l, int u, std::vector<int> w) {
  vector<pair<int, int> > indexedWeights;
  for (int i = 0; i < w.size(); i++) {
    indexedWeights.push_back({w[i], i});
  }

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

  vector<LL> prefixSum;
  prefixSum.push_back(indexedWeights[0].first);

  for (int i = 1; i < indexedWeights.size(); i++) {
    prefixSum.push_back(indexedWeights[i].first + prefixSum.back());
  }

  for (int i = 0; i < indexedWeights.size(); i++) {
    int lo = i, hi = indexedWeights.size() - 1, mid;
    while (hi >= lo) {
      mid = (lo + hi)/2;
      LL sum = prefixSum[mid] - (i == 0 ? 0 : prefixSum[i - 1]);

      if (sum < l) {
        lo = mid + 1;
      } else {
        hi = mid - 1;
      }
    }

    LL sum = prefixSum[lo] - (i == 0 ? 0 : prefixSum[i - 1]);
    if (sum >= l && sum <= u) {
      vector<int> result;
      for (int j = i; j <= lo; j++) {
        result.push_back(indexedWeights[j].second);
      }
      return result;
    }
  }

  vector<int> result;
  return result;
}

Compilation message (stderr)

molecules.cpp: In function 'std::vector<int> find_subset(int, int, std::vector<int>)':
molecules.cpp:8:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 |   for (int i = 0; i < w.size(); i++) {
      |                   ~~^~~~~~~~~~
molecules.cpp:17:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |   for (int i = 1; i < indexedWeights.size(); i++) {
      |                   ~~^~~~~~~~~~~~~~~~~~~~~~~
molecules.cpp:21:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |   for (int i = 0; i < indexedWeights.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