56. Merge Intervals（js）

56. Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

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.
题意：将重叠的区间的两个数组合并，
代码如下：

/**
 * Definition for an interval.
 * function Interval(start, end) {
 *     this.start = start;
 *     this.end = end;
 * }
 */
/**
 * @param {Interval[]} intervals
 * @return {Interval[]}
 */
var merge = function(intervals) {
    if(intervals.length===0 || intervals===null) return intervals;
    var res=[];
    intervals.sort(function(a,b){
        return a.start-b.start;
    })

    res.push(intervals[0]);
    for(var i=1;i<intervals.length;i++){
        if(intervals[i].start>res[res.length-1].end){
            res.push(intervals[i]);
        }else{
            res[res.length-1].end=Math.max(intervals[i].end,res[res.length-1].end);
        }
    }
    return res;
    
};