How do you polar sort?

Правка en10, от Alpha_Q, 2020-01-05 00:21:53

Say yo want a set of points sorted in some counterclockwise order. What is the best (fast, precise, short) way to do it? The atan2l function is precise and short but way too slow.

Update: I like the following one.

inline bool up (point p) {
  return p.y > 0 or (p.y == 0 and p.x >= 0);
}

sort(v.begin(), v.end(), [] (point a, point b) {
  return up(a) == up(b) ? a.x * b.y > a.y * b.x : up(a) < up(b);
});
Теги geometry, godblessamerica

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  Rev. Язык Кто Когда Δ Комментарий
en11 Английский Alpha_Q 2020-01-05 00:33:03 62
en10 Английский Alpha_Q 2020-01-05 00:21:53 237 Reverted to en7
en9 Английский Alpha_Q 2020-01-05 00:18:40 37 Tiny change: '});\n~~~~~' -> '});\n~~~~~\n\nReference: [submission:68213997].'
en8 Английский Alpha_Q 2020-01-05 00:16:42 200
en7 Английский Alpha_Q 2020-01-04 23:59:16 539 Tiny change: ' too slow. \n\n**Upda' -> ' too slow.\n\n**Upda'
en6 Английский Alpha_Q 2020-01-04 23:27:29 8
en5 Английский Alpha_Q 2020-01-04 23:25:59 41
en4 Английский Alpha_Q 2020-01-04 23:23:45 13 Tiny change: 'g version (way longer) seems to ' -> 'g version seems to '
en3 Английский Alpha_Q 2020-01-04 23:22:23 291
en2 Английский Alpha_Q 2020-01-04 23:00:16 504 Tiny change: '});\n~~~~~' -> '});\n~~~~~\n'
en1 Английский Alpha_Q 2020-01-04 21:38:47 467 Initial revision (published)