よく忘れる

lambda.cc

// basic
float min = *std::min_element(v.begin(),v.end(),[](Type msg1, Type msg2) {return msg1.second > msg2.second };
float sum = std::accumulate(v.begin(), v.end(),0,[](const int sum, const Type& msg){ return sum + msg.second; })
// index sort                              
template<typename T>
std::vector<size_t> sort_index(std::vector<T> const& values) {
  std::vector<size_t> indices(values.size());
  std::iota(indices.begin(), indices.end(), static_cast<size_t>(0)); // init index
  std::sort(indices.begin(), indices.end(), [&](size_t a, size_t b) { return values[a] < values[b]; }); // 昇順？
  return indices;
}
                              
// self-defined operator                              
struct myclass {
    bool operator() (cv::Point pt1, cv::Point pt2) { return (pt1.y < pt2.y);}
} myobject;
                              
// object-operator                              
struct msg {
  float res;
  float x;
  float y;

  cv::Vec<float, _LABEL_MAX_NUM_> values;
  msg()             : res(0.0) {};
  msg(float res_)    : res(res_) {};
  msg(int x_, int y_) : res(0.0), x(x_), y(y_) {};

  bool operator<(const msg& m) const { return res > m.res; };
};
                              
int main () {
    // input data
    std::vector<cv::Point> pts(5);
    pts[0] = Point(10,40);
    pts[1] = Point(9,27);
    pts[2] = Point(5,68);
    pts[3] = Point(7,55);
    pts[4] = Point(8,15);

    // sort vector using myobject as comparator
    std::sort(pts.begin(), pts.end(), myobject);
    
    // sorted by res
    std::priority_queue<msg> pq;
    pq.push(msg(3));
    pq.push(msg(2));
    pq.push(msg(100));
    pq.push(msg(10));
}