LeetCode刷题【Array】 Merge Intervals

题目：

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].

解决方法： Runtime:  97 ms

/**
 * 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; }
 * }
 */
public class Solution {
	    public List<Interval> merge(List<Interval> intervals) {
	    	List<Interval> ret= new ArrayList<Interval>();
			intervals.sort((x,y)->{return x.start -y.start;});
			
			Interval a =null;
			for(int i=0;i<intervals.size();i++){
				if(null==a)
					a=intervals.get(i);
				else{
					Interval temp = intervals.get(i);
					if(temp.start>a.end){
						ret.add(a);
						a=temp;
					}else if(temp.end<a.end){
						continue;
					}else if(temp.end>=a.end){
						Interval mergeRet = new Interval(a.start,temp.end);
						a=mergeRet;
					}
				}
			}
			if(a!=null) ret.add(a);
			return ret;
	    }
	}

参考：

【1】https://leetcode.com/