56.Merge_Intervals.java

class Solution {
    public int[][] merge(int[][] intervals) {
        Arrays.sort(intervals, (a,b) -> a[0] - b[0]);
        List<int[]> res = new ArrayList<>();
        int[] curr = null;
        for (int[] ival : intervals) {
            if (curr == null) {
                curr = ival;
            } else {
                if (curr[1] < ival[0]) {
                    res.add(curr);
                    curr = ival;
                } else {
                    curr[0] = Math.min(curr[0], ival[0]);
                    curr[1] = Math.max(curr[1], ival[1]);
                }
            }
        }
        if (curr != null) {
            res.add(curr);
        }
        return res.toArray(new int[0][2]);
    }
}