wownero/src/common/combinator.cpp

// Copyright (c) 2018, The Monero Project
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// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers

#include "combinator.h"

namespace tools {

uint64_t combinations_count(uint32_t k, uint32_t n)
{
  if (k > n) {
    throw std::runtime_error("k must not be greater than n");
  }

  uint64_t c = 1;
  for (uint64_t i = 1; i <= k; ++i) {
    c *= n--;
    c /= i;
  }

  return c;
}

}