060_permutation_sequence.py 文件源码

def getPermutation(self, n, k):
        """
        :type n: int
        :type k: int
        :rtype: str
        """
        numbers = range(1, n+1)
        permutation = ''
        k -= 1
        while n > 0:
            n -= 1
            # get the index of current digit
            index, k = divmod(k, math.factorial(n))
            permutation += str(numbers[index])
            # remove handled number
            numbers.remove(numbers[index])

        return permutation