37 lines
746 B
Markdown
37 lines
746 B
Markdown
---
|
|
title: lcm
|
|
tags: math,list,recursion,advanced
|
|
---
|
|
|
|
Returns the least common multiple of two or more numbers.
|
|
|
|
Define a function, `spread`, that uses either `list.extend()` or `list.append()` on each element in a list to flatten it.
|
|
Use `math.gcd()` and `lcm(x,y) = x * y / gcd(x,y)` to determine the least common multiple.
|
|
|
|
```py
|
|
from functools import reduce
|
|
import math
|
|
|
|
def spread(arg):
|
|
ret = []
|
|
for i in arg:
|
|
if isinstance(i, list):
|
|
ret.extend(i)
|
|
else:
|
|
ret.append(i)
|
|
return ret
|
|
|
|
def lcm(*args):
|
|
numbers = []
|
|
numbers.extend(spread(list(args)))
|
|
|
|
def _lcm(x, y):
|
|
return int(x * y / math.gcd(x, y))
|
|
|
|
return reduce((lambda x, y: _lcm(x, y)), numbers)
|
|
```
|
|
|
|
```py
|
|
lcm(12, 7) # 84
|
|
lcm([1, 3, 4], 5) # 60
|
|
``` |