Leetcode 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:

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.

Code (Java):

class Solution {
    public int findMinDifference(List<String> timePoints) {
        boolean[] minutes = new boolean[1440];

        for (String time : timePoints) {
            int minute = convertToMinutes(time);
            if (minutes[minute]) {
                return 0;
            }

            minutes[minute] = true;
        }

        // iterate through the minutes and find the minimum findMinDifference
        //
        int prev = -1;
        int first = -1;
        int curr = -1;
        int min = Integer.MAX_VALUE;
        for (int i = 0; i < minutes.length; i++) {
            if (prev == -1) {
                if (minutes[i] == true) {
                    prev = i;
                    first = i;
                }
                continue;
            }

            if (minutes[i]) {
                curr = i;
                int diff = i - prev;
                diff = Math.min(diff, 1440 - diff);
                min = Math.min(min, diff);
                prev = i;
            }
        }
        int diff = curr - first;
        min = Math.min(min, Math.min(diff, 1440 - diff));

        return min;
    }

    private int convertToMinutes(String s) {
        String[] tokens = s.split("[:]");
        int hour = Integer.parseInt(tokens[0]);
        int minute = Integer.parseInt(tokens[1]);

        return hour * 60 + minute;
    }
}