import java.util.ArrayList;

import java.util.Arrays;

import java.util.Comparator;

import java.util.List;

public class MergeArrays {

public static void main(String[] args) {

int[][] intervals = new int[][]{{2, 6}, {1, 3}, {8, 10}, {15, 18}};

// 输出：[[1,6],[8,10],[15,18]]

List<List<Integer>> ret = resolve(intervals);

for (List<Integer> l : ret) {

System.out.println(Arrays.toString(l.toArray()));

}

}

public static List<List<Integer>> resolve(int[][] intervals) {

if (intervals == null || intervals.length == 0) {

return new ArrayList<>();

}

Arrays.sort(intervals, Comparator.comparingInt(interval -> interval[0]));

List<List<Integer>> ret = new ArrayList<>();

for (int i = 0; i < intervals.length; i++) {

int L = intervals[i][0];

int R = intervals[i][1];

if (ret.size() == 0 || ret.get(ret.size() - 1).get(1) < L) {

ret.add(Arrays.asList(L, R));

} else {

ret.get(ret.size() - 1).set(1, Math.max(R, ret.get(ret.size() - 1).get(1)));

}

}

return ret;

}

}