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Side proportions solution in Clear category for Similar Triangles by amandel
from typing import List, Tuple
Coords = List[Tuple[int, int]]
# will stick to integer arithmetic only
def similar_triangles(coords_1: Coords, coords_2: Coords) -> bool:
def side2(x,y):
return (x[0]-y[0])**2+(x[1]-y[1])**2
def sig(u):
return sorted([side2(u[0],u[1]),side2(u[2],u[1]),side2(u[0],u[2])])
a1,a2,a3 = sig(coords_1)
b1,b2,b3 = sig(coords_2)
return a1*b2==a2*b1 and a1*b3==a3*b1
if __name__ == '__main__':
print("Example:")
print(similar_triangles([(0, 0), (1, 2), (2, 0)], [(3, 0), (4, 2), (5, 0)]))
# These "asserts" are used for self-checking and not for an auto-testing
assert similar_triangles([(0, 0), (1, 2), (2, 0)], [(3, 0), (4, 2), (5, 0)]) is True, 'basic'
assert similar_triangles([(0, 0), (1, 2), (2, 0)], [(3, 0), (4, 3), (5, 0)]) is False, 'different #1'
assert similar_triangles([(0, 0), (1, 2), (2, 0)], [(2, 0), (4, 4), (6, 0)]) is True, 'scaling'
assert similar_triangles([(0, 0), (0, 3), (2, 0)], [(3, 0), (5, 3), (5, 0)]) is True, 'reflection'
assert similar_triangles([(1, 0), (1, 2), (2, 0)], [(3, 0), (5, 4), (5, 0)]) is True, 'scaling and reflection'
assert similar_triangles([(1, 0), (1, 3), (2, 0)], [(3, 0), (5, 5), (5, 0)]) is False, 'different #2'
print("Coding complete? Click 'Check' to earn cool rewards!")
Jan. 14, 2022
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