【leetcode】 Merge Intervals

Merge Intervals 

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].

解题思路： 根据start对区间进行排序，然后依次遍历进行区间合并。

/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
bool cmp(const Interval &a, const Interval &b){
    return a.start < b.start;
}
class Solution {
public:
    vector<Interval> merge(vector<Interval> &intervals) {
        if(intervals.size() == 0)
            return intervals;
            sort(intervals.begin(), intervals.end(), cmp);
        vector<Interval> result;
        Interval mover = intervals[0];
        for(int i = 1; i < intervals.size(); ++i){
            if(mover.end < intervals[i].start){
                result.push_back(mover);
                mover = intervals[i];
            }else{
                mover.end = max(mover.end, intervals[i].end);
            }
        }
        result.push_back(mover);
        return result;
    }
};