Submission #897949

#	Time	Username	Problem	Language	Result	Execution time	Memory
897949		duckindog	Detecting Molecules (IOI16_molecules)	C++14	0 / 100	1 ms	2396 KiB

molecules

// from duckindog wth depression
#include<bits/stdc++.h>

using namespace std;

//#define LOCAL

#ifndef LOCAL
#include "molecules.h"
#endif // LOCAL

struct T {
  int a, b;

  T(int aa, int bb) : a(aa), b(bb) {}
};
const int N = 1e4 + 1;
bool f[2][N];
pair<int, int> trace[N][N];
vector<int> find_subset(int l, int u, vector<int> w) {
  int n = w.size();

  for (int i = 1; i < n; ++i) {
    int it = i + 1 & 1;
    f[1 - it][0] = f[1 - it][w[i - 1]] = 1;
    for (int j = 1; j <= u; ++j) {
      auto &ret = f[it][j];
      if (f[1 - it][j]) {
        ret = 1;
        trace[i][j] = {i - 1, j};
      }
      if (j - w[i] >= 0 && f[1 - it][j - w[i]]) {
        ret = 1;
        trace[i][j] = {i - 1, j - w[i]};
      }
    }
  }

  vector<int> answer;
  int i = n - 1, j = 0;
  for (int x = l; x <= u; ++x) if (f[n - 1 & 1][x]) j = x;

  if (!j) return answer;

  while (j) {
    int pi, pj; tie(pi, pj) = trace[i][j];
    if (j > pj) answer.push_back(i);
    i = pi; j = pj;
  }
  return answer;
}

#ifdef LOCAL
int32_t main() {
  cin.tie(0)->sync_with_stdio(0);

  if (fopen("duck.inp", "r")) {
    freopen("duck.inp", "r", stdin);
    freopen("duck.out", "w", stdout);
  }

  for (auto x : find_subset(10, 20, {15, 17, 16, 18}))
    cout << x << ' ';
}
#endif // LOCAL

Compilation message (stderr)

molecules.cpp: In function 'std::vector<int> find_subset(int, int, std::vector<int>)':
molecules.cpp:24:16: warning: suggest parentheses around '+' in operand of '&' [-Wparentheses]
   24 |     int it = i + 1 & 1;
      |              ~~^~~
molecules.cpp:41:40: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   41 |   for (int x = l; x <= u; ++x) if (f[n - 1 & 1][x]) j = x;
      |                                      ~~^~~

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