LeetCode 56 Merge Intervals

原题:（频率5）

Given a collection of intervals, merge all overlapping intervals.
For example,

Given 

[1,3],[2,6],[8,10],[15,18]

,

return 

[1,6],[8,10],[15,18]

.

题意：给一个intervals的集合，合并所有重叠的。

代码和思路：

/**
* Definition for an interval.
* public class Interval {
* int start;
* int end;
* Interval() { start = 0; end = 0; }
* Interval(int s, int e) { start = s; end = e; }
* }
*/
class Solution {
public List<Interval> merge(List<Interval> intervals) {
if(intervals.size()<=1){
return intervals;
}
//按start大小排序
intervals.sort((i1, i2) -> Integer.compare(i1.start, i2.start));

List<Interval> result = new LinkedList<>();

int start = intervals.get(0).start;
int end = intervals.get(0).end;

for(Interval i:intervals){
if(i.start <= end){
end = Math.max(end,i.end);
}
else{
result.add(new Interval(start,end));
start = i.start;
end = i.end;
}
}
//因为循环中会漏加最后一组，这里加上
result.add(new Interval(start,end));
return result;
}
}