fork download
copy 
  1. #include <iostream>
  2. #include <cstdint>
  3. using namespace std;
  4.  
  5. uint64_t sequence(uint64_t A, uint64_t B, size_t n) {
  6.  if (n == 0) {
  7.   return A;
  8.  }
  9.  uint64_t prev[2] = {A, B};
  10.  for (size_t it = 1u; it < n; ++it) {
  11.   uint64_t next =
  12.     (prev[0] > prev[1]) ?
  13.       (prev[0] - prev[1]) :
  14.       (prev[1] - prev[0]);
  15.   if (next == 0) {
  16.    size_t remaining = n - it - 1;
  17.    if (remaining % 3 == 0) {
  18.     return 0;
  19.    }
  20.    return prev[0];
  21.   }
  22.   prev[0] = prev[1];
  23.   prev[1] = next;
  24.  }
  25.  return prev[1];
  26. }
  27.  
  28. uint64_t sequence_control(uint64_t A, uint64_t B, size_t n) {
  29.  if (n == 0) {
  30.   return A;
  31.  }
  32.  uint64_t prev[2] = {A, B};
  33.  for (size_t it = 1u; it < n; ++it) {
  34.   uint64_t next =
  35.     (prev[0] > prev[1]) ?
  36.       (prev[0] - prev[1]) :
  37.       (prev[1] - prev[0]);
  38.   prev[0] = prev[1];
  39.   prev[1] = next;
  40.  }
  41.  return prev[1];
  42. }
  43.  
  44.  
  45. int main(int, char **) {
  46.  uint64_t a = 211;
  47.  uint64_t b = 9935;
  48.  for (size_t n = 0; n < 10000; ++n) {
  49.   auto s = sequence(a,b,n);
  50.   auto c = sequence_control(a,b,n);
  51.   if (c != s) {
  52.    cout << a << "|" << b << "  " << n << ": c = " << c << "  s = " << s << endl;
  53.   }
  54.  }
  55.  return 0;
  56. }
Success #stdin #stdout 0.14s 3136KB
comments ()
stdin
copy 
Standard input is empty
stdout
copy 
Standard output is empty
https://ideone.com/VlO5Gy
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!