0056 - Merge Intervals

0056 - Merge Intervals

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

Examples

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].

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

Constraints

• 1 <= intervals.length <= 104

• intervals[i].length == 2

• 0 <= starti <= endi <= 104

Java Solution

class Solution {
    public int[][] merge(int[][] intervals) {
        Arrays.sort(intervals, (a,b) -> Integer.compare(a[0], b[0]));
        
        LinkedList<int[]> result = new LinkedList<>();
        
        for(int[] interval : intervals) {
            if(result.isEmpty() || result.getLast()[1] < interval[0]) result.add(interval);
            else result.getLast()[1] = Math.max(result.getLast()[1], interval[1]);
        }
        return result.toArray(new int[result.size()][]);
    }
}