Minimum Time Difference - DP(ish) solution

Problem is here: https://leetcode.com/problems/minimum-time-difference/description/

Given a list of 24-hour clock time points in "Hour:Minutes" format, find the minimum minutes difference between any two time points in the list.

Example 1:

Input: ["23:59","00:00"]
Output: 1

Note:

1. The number of time points in the given list is at least 2 and won't exceed 20000.
2. The input time is legal and ranges from 00:00 to 23:59.

Despite being a medium-complexity problem, there is a way to do it in linear time using concepts of DP:

• Basically the input range is very small: it fits into a 1500 array
• Create a bool array of this size and map each time to it
• If the time has already been set, return 0 (that's the min)
• This cost linear time and constant space (O(1500))
• Next traverse the array and compare the two adjacent cells that have a time on it
• Some extra check is needed for the boundary case when the min diff crosses the day line

That's it! Cheers, Marcelo

public class Solution
{
 public int FindMinDifference(IList timePoints)
 {
  if (timePoints == null) return 0;

  bool[] map = new bool[1500];

  int min = Int32.MaxValue;
  int max = Int32.MinValue;
  foreach (string t in timePoints)
  {
   string[] parts = t.Split(':');
   int val = Int32.Parse(parts[0]) * 60 + Int32.Parse(parts[1]);

   if (map[val]) return 0;
   map[val] = true;

   min = Math.Min(min, val);
   max = Math.Max(max, val);
  }

  int solution = Math.Abs(24 * 60 - (max - min));
  int previousIndex = min;
  for (int i = min + 1; i < map.Length; i++)
  {
   if (map[i])
   {
    solution = Math.Min(solution, i - previousIndex);
    previousIndex = i;
   }
  }

  return solution;
 }
}