539. Minimum Time Difference.md

539. Minimum Time Difference

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:

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

Solution

• Java

  • mine Runtime: 12 ms, faster than 52.90% of Java online submissions

  class Solution {
    public int findMinDifference(List<String> timePoints) {
        int len = timePoints.size();
        int[] array = new int[len];
        for (int i = 0; i < len; i++) {
            array[i] = format(timePoints.get(i));
        }
        Arrays.sort(array);
        int res = Integer.MAX_VALUE;
        int t;
        for (int i = 0; i < len; i++) {
            t = Math.abs(array[i] - array[(i + 1) % len]);
            if (t > 12 * 60) {
                t = 24 * 60 - t;
            }
            res = Math.min(res, t);
        }
        return res;
    }
  
    private int format(String s) {
        String[] a = s.split(":");
        return Integer.parseInt(a[0]) * 60 + Integer.parseInt(a[1]);
    }
  }
  

  • most votes Runtime: 4 ms, faster than 89.39% of Java online submissions

  public class Solution {
      public int findMinDifference(List<String> timePoints) {
          boolean[] mark = new boolean[24 * 60];
          for (String time : timePoints) {
              String[] t = time.split(":");
              int h = Integer.parseInt(t[0]);
              int m = Integer.parseInt(t[1]);
              if (mark[h * 60 + m]) return 0;
              mark[h * 60 + m] = true;
          }
  
          int prev = 0, min = Integer.MAX_VALUE;
          int first = Integer.MAX_VALUE, last = Integer.MIN_VALUE;
          for (int i = 0; i < 24 * 60; i++) {
              if (mark[i]) {
                  if (first != Integer.MAX_VALUE) {
                      min = Math.min(min, i - prev);
                  }
                  first = Math.min(first, i);
                  last = Math.max(last, i);
                  prev = i;
              }
          }
  
          min = Math.min(min, (24 * 60 - last + first));
  
          return min;
      }
  }