Merge_Intervals.java

https://leetcode.com/problems/merge-intervals
class Solution {
    public int[][] merge(int[][] intervals) {
        if(intervals.length <= 1){
            return intervals;
        }
        Arrays.sort(intervals,(arr1,arr2) -> Integer.compare(arr1[0],arr2[0]));
      List<int[]> output_arr = new ArrayList();
        int [] current_interval = intervals[0];
        output_arr.add(current_interval);
        
        for(int[] interval:intervals){
            int current_begin = current_interval[0];
            int current_end = current_interval[1];
            int next_begin = interval[0];
            int next_end = interval[1];
            
            if(current_end >= next_begin){
                current_interval[1] = Math.max(current_end,next_end);
            }
            else{
                current_interval = interval;
                output_arr.add(current_interval);
            }
        
        }
        return output_arr.toArray(new int [output_arr.size()][]);
        
    }
}