math.cc

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// Copyright (c) 2018, ETH Zurich and UNC Chapel Hill.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright
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//     * Redistributions in binary form must reproduce the above copyright
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//     * Neither the name of ETH Zurich and UNC Chapel Hill nor the names of
//       its contributors may be used to endorse or promote products derived
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// Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)
 
#include "util/math.h"
 
namespace colmap {
 
size_t NChooseK(const size_t n, const size_t k) {
  if (k == 0) {
    return 1;
  }
 
  return (n * NChooseK(n - 1, k - 1)) / k;
}
 
}  // namespace colmap