Submission #974417

#	Time	Username	Problem	Language	Result	Execution time	Memory
974417		rolandpetrean	Remittance (JOI19_remittance)	C++17	55 / 100	175 ms	67656 KiB

remittance

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

using ll = long long;
#define int ll

#define endl '\n'
#define pb push_back
using pi = array<int, 2>;

const int LG = 31;
int p2[LG];

void prec() {
  p2[0] = 1;
  for (int i = 1; i < LG; ++i) p2[i] = p2[i - 1] * 2;
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  
  prec();
  
  int n;
  cin >> n;
  
  vector<int> a(n), b(n), c(n);
  for (int i = 0; i < n; ++i) {
    cin >> a[i] >> b[i];
    c[i] = b[i] - a[i];
  }
  
  assert(n <= 20);
  
  vector<int> in(n);
  for (int i = 0; i < n; ++i) {
    in[0] -= p2[i] * c[i];
  }
  
  if (in[0] % (p2[n] - 1) != 0) {
    cout << "No";
    return 0;
  }
  in[0] /= p2[n] - 1;
  
  for (int i = 1; i < n; ++i) {
    int x = in[i - 1] - c[i - 1];
    if (x % 2 != 0) {
      cout << "No";
      return 0;
    }
    in[i] = x / 2;
  }
  
  for (int i = 0; i < n; ++i) {
    if (in[i] < 0) {
      cout << "No";
      return 0;
    }
  }
  
  bool pushed = true;
  while (pushed) {
    pushed = false;
    for (int i = 0; i < n; ++i) {
      int j = (i + 1) % n;
      
      int push = min(in[j], a[i] / 2);
      a[i] -= 2 * push;
      in[j] -= push;
      a[j] += push;

      if (push != 0) pushed = true;
    }
  }
  
  for (int i = 0; i < n; ++i) {
    if (in[i] != 0) {
      cout << "No";
      return 0;
    }
  }
  
  cout << "Yes";
}

/*
in[0] = -sum{2^i * c[i]} / (2^n - 1)
0 + 2 * (-1) + 4 * (1) + 8 * (0) + 16 * (-4)
*/

• Subtask 1: 15 / 15
• Subtask 2: 40 / 40
• Subtask 3: 0 / 45