681. Next Closest Time

tags

trick

source

leetcode

Edge Cases

Solution 1

1. get digits array
2. get sorted digits array
3. scan from right to left
   1. find next greater number of digits[i] in sorted
   2. new digits array
   3. if valid, this is the answer
   4. if not valid, digits[i] will be sorted[0]

Complexity

• time: O(4 * 4) = O(1)
• space: O(8) = O(1)

Solution 2

1. boolean num[9]
2. set digits from time in num true
3. try min
   1. start from min + 1 to 60 if new min is from num, this is the answer
4. try hour
   1. min is composed by smallest number in 4 digits
   2. start from hour + 1 to 24