539. Minimum Time Difference

import java.util.*;

class Solution {

    public int findMinDifference(List<String> timePoints) {
        final int TOTAL_MINUTES = 24 * 60;
        boolean[] seen = new boolean[TOTAL_MINUTES];
        int count = 0;

        // Convert times to minutes and place them into buckets
        for (String time : timePoints) {
            int minutes = convertToMinutes(time);
            if (seen[minutes]) {
                return 0; // Duplicate times result in zero difference
            }
            seen[minutes] = true;
            count++;
        }

        if (count == 1) {
            return 0; // Only one time point, no meaningful difference
        }

        // Compute minimum difference between adjacent buckets
        int prev = -1;
        int minDiff = Integer.MAX_VALUE;
        int firstTime = -1;
        int lastTime = -1;

        for (int i = 0; i < TOTAL_MINUTES; i++) {
            if (seen[i]) {
                if (prev != -1) {
                    minDiff = Math.min(minDiff, i - prev);
                }
                prev = i;
                if (firstTime == -1) {
                    firstTime = i;
                }
                lastTime = i;
            }
        }

        // Check the difference between the last and the first bucket (wrap-around)
        if (firstTime != -1 && lastTime != -1) {
            minDiff = Math.min(minDiff, TOTAL_MINUTES - lastTime + firstTime);
        }

        return minDiff;
    }

    private int convertToMinutes(String time) {
        int h = Integer.parseInt(time.substring(0, 2));
        int m = Integer.parseInt(time.substring(3));
        return h * 60 + m;
    }

}