Watch binary leetcode-401

Watch binary leetcode-401

Subject description:

Binary watch has four top LED for hour (0-11), six bottom LED for minutes (0-59). Each LED represents a 0 or 1, the least significant bit on the right. Given a non-negative integer n represents the number of lit LED current returns all possible time.

Reference: Negative snow Ming Zhu

from itertools import combinations
class Solution:
    def readBinaryWatch(self, num: int) -> List[str]:
        
        def dfs(num,hour,res):
            if hour > num: return
            for hours in combinations([1,2,4,8],hour):
                hs = sum(hours)
                if hs >= 12: continue
                for mints in combinations([1,2,4,8,16,32],num-hour):
                    ms = sum(mints)
                    if ms >= 60: continue
                    res.append("%d:%02d"%(hs,ms))
            dfs(num,hour+1,res)
        res = []
        dfs(num,0,res)
        return res

Reference: Panda love of learning

from itertools import combinations
class Solution:
    def readBinaryWatch(self, num: int) -> List[str]:
        
        res = []
        for h in range(12):
            for m in range(60):
                if (bin(h)+bin(m)).count('1') == num:
                    res.append("%d:%02d"%(h,m))
        return res