Merge Intervals

Description

Given a collection of intervals, merge all overlapping intervals.

Example 1:

Input: intervals = [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]
Explanation: Since intervals [1,3] and [2,6] overlaps, merge them into [1,6].

Example 2:

Input: intervals = [[1,4],[4,5]]
Output: [[1,5]]
Explanation: Intervals [1,4] and [4,5] are considered overlapping.

NOTE: input types have been changed on April 15, 2019. Please reset to default code definition to get new method signature.

 

Constraints:

• intervals[i][0] <= intervals[i][1]

Solution(javascript)

const merge = (intervals = []) => {
  if (intervals.length === 0) {
    return intervals
  }
  intervals.sort(([a], [c]) => a - c)
  const result = [intervals[0]]
  let index = 1
  while (index <= intervals.length - 1) {
    const [a, b] = result[result.length - 1]
    const [c, d] = intervals[index]
    if (a <= c && c <= b) {
      result[result.length - 1] = [a, Math.max(b, d)]
    } else {
      result.push(intervals[index])
    }
    index += 1
  }
  return result
}