题意:重叠的interval可以合并在一起
Example 1:
Input: [[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].
Example 2:
Input: [[1,4],[4,5]]
Output: [[1,5]]
Explanation: Intervals [1,4] and [4,5] are considered overlapping.
public List<Interval> merge(List<Interval> intervals) {
//考虑边界情况
if (intervals.size() <= 1)
return intervals;
// Sort by ascending starting point using an anonymous Comparator
intervals.sort((i1, i2) -> Integer.compare(i1.start, i2.start));
List<Interval> result = new LinkedList<Interval>();
//拿到第一个interval的开始和结尾
int start = intervals.get(0).start;
int end = intervals.get(0).end;
for (Interval interval : intervals) {
//比较当前interval和上一次end的大小,如果有重叠
if (interval.start <= end) // Overlapping intervals, move the end if needed
//更新end
end = Math.max(end, interval.end);
//没有重叠的话
else { // Disjoint intervals, add the previous one and reset bounds
//result中直接加入上一次的start 和 end
result.add(new Interval(start, end));
//更新start 和 end
start = interval.start;
end = interval.end;
}
}
// Add the last interval
result.add(new Interval(start, end));
return result;
}