## lc 60 - permutation sequence

the trick is to use the condition "The set [1,2,3,...,n] contains a total of n! unique permutations." ```python import math class Solution: def getPermutation(self, n: int, k: int) -> str: k-=1 l=list(range(1,n+1)) o='' for p in range(n): f=int(math.factorial(n-p-1)) x, k = k//f, k%f o+=str(l[x]) l.remove(l[x]) return o ```