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First-StanislauL solution in Clear category for The Cheapest Flight by StanislauL
from typing import List
def cheapest_flight(costs: List, a: str, b: str) -> int:
res = {a: 0}
def solver(dest):
if not dest:
return res.get(b, 0)
destT = set()
for city in dest:
for route in costs:
if city in route:
tmp = route[0] if city==route[1] else route[1]
if tmp in res:
if res[city] + route[2] < res[tmp]:
res[tmp] = res[city] + route[2]
destT.add(tmp)
else:
res[tmp] = res[city] + route[2]
destT.add(tmp)
return solver(destT)
return solver({a})
if __name__ == '__main__':
print("Example:")
print(cheapest_flight([['A', 'C', 100],
['A', 'B', 20],
['B', 'C', 50]],
'A',
'C'))
# These "asserts" are used for self-checking and not for an auto-testing
assert cheapest_flight([['A', 'C', 100],
['A', 'B', 20],
['B', 'C', 50]],
'A',
'C') == 70
assert cheapest_flight([['A', 'C', 100],
['A', 'B', 20],
['B', 'C', 50]],
'C',
'A') == 70
assert cheapest_flight([['A', 'C', 40],
['A', 'B', 20],
['A', 'D', 20],
['B', 'C', 50],
['D', 'C', 70]],
'D',
'C') == 60
assert cheapest_flight([['A', 'C', 100],
['A', 'B', 20],
['D', 'F', 900]],
'A',
'F') == 0
assert cheapest_flight([['A', 'B', 10],
['A', 'C', 15],
['B', 'D', 15],
['C', 'D', 10]],
'A',
'D') == 25
print("Coding complete? Click 'Check' to earn cool rewards!")
March 3, 2021
