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[mypy-fix] Type fixes for graham_scan (#5589)

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* [mypy] Fixes type annotations in other/graham_scan  #4052

+ Prefer tuple to list for point x,y pairs

* NOP: fixes typo in comment
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Andrew Grangaard 2021-10-26 02:50:36 -07:00 committed by GitHub
parent f93c7d4d80
commit 2606f1bbe5
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1 changed files with 13 additions and 13 deletions
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26
other/graham_scan.py
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@ -14,7 +14,7 @@ from math import atan2, degrees
from sys import maxsize
def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
def graham_scan(points: list[tuple[int, int]]) -> list[tuple[int, int]]:
"""Pure implementation of graham scan algorithm in Python
:param points: The unique points on coordinates.
@ -57,7 +57,7 @@ def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
# remove the lowest and the most left point from points for preparing for sort
points.pop(minidx)
def angle_comparer(point: list[int, int], minx: int, miny: int) -> float:
def angle_comparer(point: tuple[int, int], minx: int, miny: int) -> float:
"""Return the angle toward to point from (minx, miny)
:param point: The target point
@ -66,13 +66,13 @@ def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
:return: the angle
Examples:
>>> angle_comparer([1,1], 0, 0)
>>> angle_comparer((1,1), 0, 0)
45.0
>>> angle_comparer([100,1], 10, 10)
>>> angle_comparer((100,1), 10, 10)
-5.710593137499642
>>> angle_comparer([5,5], 2, 3)
>>> angle_comparer((5,5), 2, 3)
33.690067525979785
"""
# sort the points accorgind to the angle from the lowest and the most left point
@ -83,7 +83,7 @@ def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
sorted_points = sorted(points, key=lambda point: angle_comparer(point, minx, miny))
# This insert actually costs complexity,
# and you should insteadly add (minx, miny) into stack later.
# and you should instead add (minx, miny) into stack later.
# I'm using insert just for easy understanding.
sorted_points.insert(0, (minx, miny))
@ -95,7 +95,7 @@ def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
right = 3
def check_direction(
starting: list[int, int], via: list[int, int], target: list[int, int]
starting: tuple[int, int], via: tuple[int, int], target: tuple[int, int]
) -> Direction:
"""Return the direction toward to the line from via to target from starting
@ -105,13 +105,13 @@ def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
:return: the Direction
Examples:
>>> check_direction([1,1], [2,2], [3,3])
>>> check_direction((1,1), (2,2), (3,3))
Direction.straight
>>> check_direction([60,1], [-50,199], [30,2])
>>> check_direction((60,1), (-50,199), (30,2))
Direction.left
>>> check_direction([0,0], [5,5], [10,0])
>>> check_direction((0,0), (5,5), (10,0))
Direction.right
"""
x0, y0 = starting
@ -132,12 +132,12 @@ def graham_scan(points: list[list[int, int]]) -> list[list[int, int]]:
# If they are same, it means they are on a same line of convex hull.
if target_angle > via_angle:
return Direction.left
if target_angle == via_angle:
elif target_angle == via_angle:
return Direction.straight
if target_angle < via_angle:
else:
return Direction.right
stack = deque()
stack: deque[tuple[int, int]] = deque()
stack.append(sorted_points[0])
stack.append(sorted_points[1])
stack.append(sorted_points[2])