539. Minimum Time Difference

Description

Given a list of 24-hour clock time points in "HH:MM" format, return the minimum minutes difference between any two time-points in the list.

 

Example 1:

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

Example 2:

Input: timePoints = ["00:00","23:59","00:00"]
Output: 0

 

Constraints:

• 2 <= timePoints.length <= 2 * 104
• timePoints[i] is in the format "HH:MM".

 

Solutions

Solution: Math

• Time complexity: O(Max(n,24*60))
• Space complexity: O(24*60)

 

JavaScript

/**
 * @param {string[]} timePoints
 * @return {number}
 */
const findMinDifference = function (timePoints) {
  const MAX_MINUTE = 24 * 60;
  const n = timePoints.length;
  const times = Array.from({length: MAX_MINUTE + 1}).fill(false);
  let result = MAX_MINUTE;
  let minTime = MAX_MINUTE;

  for (let index = 0; index < n; index++) {
    const [hour, minute] = timePoints[index].split(':');
    const time = hour * 60 + +minute;

    if (times[time]) return 0;
    times[time] = true;
    minTime = Math.min(time, minTime);
  }
  let previous = minTime;

  for (let time = 1; time < times.length; time++) {
    if (!times[time] || time === minTime) continue;

    result = Math.min(time - previous, result);
    previous = time;
  }
  const headTailDiff = minTime - previous + MAX_MINUTE;

  return Math.min(result, headTailDiff);
};