Method kd_tree

code/data-structures/kd_tree.cpp:44–45

kd_tree() : root(NULL) { }

  node *root;
  // kd_tree() : root(NULL) { }
  kd_tree(vector<pt> pts) {
    root = construct(pts, 0, (int)size(pts) - 1, 0); }
  node* construct(vector<pt> &pts, int from, int to, int c) {
    if (from > to) return NULL;
    int mid = from + (to - from) / 2;