递归和回溯_leetcode401

class Solution(object):
    def readBinaryWatch(self, num):
        """
        :type num: int
        :rtype: List[str]
        """
        hour = [1,2,4,8]
        minute = [1,2,4,8,16,32]

        self.resHour = {}
        self.resMinute = {}

        self.res = []

        if num < 0 or num >= 9:
            return self.res

        if num == 0:
            return ["0:00"]

        for i in range(1,5):
            self.generateKHour(hour,i,0,[])

        for i in range(1,7):
            self.generateKMinute(minute,i,0,[])

        self.resHour[0] = [0]
        self.resMinute[0] = [0]


        for i in range(0,4):
            curHour = self.resHour[i]
            minuteIndex = num - i
            if minuteIndex >= 0 and minuteIndex <= 5:
                curMinute = self.resMinute[minuteIndex]

                for h in curHour:
                    for m in curMinute:
                        if m < 10:
                            ans = str(h) + ":" + "0" + str(m)
                        else:
                            ans = str(h) + ":"  + str(m)

                        self.res.append(ans)

            else:
                continue



        print self.resHour
        print self.resMinute

        print self.res

        return self.res

    def generateKHour(self,nums,k,start,ans):

        if len(ans) == k:
            if sum(ans) >= 0 and sum(ans) <= 11:
                if self.resHour.has_key(k):
                    self.resHour[k].append(sum(ans))
                else:
                    self.resHour[k] = [sum(ans)]
            else:
                return

        for i in range(start,len(nums)):
            ans.append(nums[i])
            self.generateKHour(nums,k,i+1,ans)
            ans.pop()


    def generateKMinute(self,nums,k,start,ans):

        if len(ans) == k:
            if sum(ans) >= 0 and sum(ans) <= 59:
                if self.resMinute.has_key(k):
                    self.resMinute[k].append(sum(ans))
                else:
                    self.resMinute[k] = [sum(ans)]
            else:
                return

        for i in range(start,len(nums)):
            ans.append(nums[i])
            self.generateKMinute(nums,k,i+1,ans)
            ans.pop()






s = Solution()

s.readBinaryWatch(1)