Complete 'bentley_ottmann.sweep' function

lycantropos · Mar 26, 2021 · d77508d · d77508d
1 parent bf810c7
commit d77508d
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Showing 2 changed files with 16 additions and 6 deletions.
diff --git a/bentley_ottmann/core/bentley_ottmann.py b/bentley_ottmann/core/bentley_ottmann.py
@@ -1,4 +1,5 @@
-from itertools import combinations
+from itertools import (chain,
+                       product)
 from typing import (Iterable,
                     List,
                     Optional,
@@ -11,6 +12,7 @@
 from .event import Event
 from .events_queue import EventsQueue
 from .sweep_line import SweepLine
+from .utils import to_pairs_combinations
 
 
 def sweep(segments: Sequence[Segment],
@@ -25,13 +27,15 @@ def sweep(segments: Sequence[Segment],
     while events_queue:
         event = events_queue.pop()
         start = event.start
-        same_start_events = (prev_same_start_events + [event]
-                             if start == prev_start
-                             else [event])
+        same_start_events = [event]
         while events_queue and events_queue.peek().start == start:
             same_start_events.append(events_queue.pop())
-        for event, other_event in combinations(same_start_events,
-                                               r=2):
+        for event, other_event in (
+                chain(to_pairs_combinations(same_start_events),
+                      product(same_start_events,
+                              prev_same_start_events))
+                if start == prev_start
+                else to_pairs_combinations(same_start_events)):
             if event.segments_ids is not other_event.segments_ids:
                 relation = segments_relater(
                         event.original_start, event.original_end,

diff --git a/bentley_ottmann/core/utils.py b/bentley_ottmann/core/utils.py
@@ -1,3 +1,5 @@
+from functools import partial
+from itertools import combinations
 from typing import (Hashable,
                     Iterable,
                     Tuple,
@@ -25,5 +27,9 @@ def pairwise(ids: Iterable[_T]) -> Iterable[Tuple[_T, _T]]:
         value = next_value
 
 
+to_pairs_combinations = partial(combinations,
+                                r=2)
+
+
 def to_sorted_pair(first: _T, second: _T) -> Tuple[_T, _T]:
     return (first, second) if first < second else (second, first)