[leetcode] 56. Merge Intervals 解题报告

题目链接：

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].

思路：还是比较简单的思路，不过要注意区间首先要排序．

代码如下：

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