leetcode56.合并区间-java

 1 class Solution {
 2     public int[][] merge(int[][] intervals) {
 3         /*
 4             思路：左区间排序，若intervals[i][0] >= intervals[i-1][1]; 则重叠
 5             将重叠区间新建放入res数组里，没重叠则放入原数组 
 6         */
 7         List<int[]> res = new LinkedList<>();
 8         Arrays.sort(intervals, (a,b) -> Integer.compare(a[0], b[0]));
 9         //initial start 是最小左边界
10         int start = intervals[0][0];
11         int rightmostRightBound = intervals[0][1];
12         for(int i = 1; i < intervals.length; i++) {
13              //如果左边界大于最大右边界
14              if(intervals[i][0] > rightmostRightBound) {//没重叠
15                 //加入区间 并且更新start
16                 res.add(new int[]{start, rightmostRightBound});
17                 start = intervals[i][0];
18                 rightmostRightBound = intervals[i][1];
19              } else {
20                 //更新最大右边界
21                 rightmostRightBound = Math.max(rightmostRightBound, intervals[i][1]);
22              }
23         }
24         res.add(new int[]{start, rightmostRightBound});
25         return res.toArray(new int[res.size()][]);
26     }
27 }