LC949 Largest Time for Given Digits

class Solution:
    def largestTimeFromDigits(self, A: List[int]) -> str:
        #time O(1) since length is 4 space O(1) 
        # main idea: use feature of time ==> hour <24 and minute <60  to filter out invalid time. then find max time by comparing time (converted to minutes) 
        max_minut = -1
        res = ""
        for i,j,k,l in itertools.permutations(A):
            hour = i*10 + j
            minut = k*10 + l
            if hour < 24 and minut < 60:
                max_minut = max(max_minut, hour*60+minut)
        if max_minut == -1:
            return res
        else:
            return "{:02d}:{:02d}".format(max_minut//60,max_minut%60)