#Leetcode# 56. Merge Intervals

https://leetcode.com/problems/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.

代码：

/**
 * 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) {
        if (intervals.empty()) return {};
        sort(intervals.begin(), intervals.end(), [](Interval &a, Interval &b) {return a.start < b.start;});
        vector<Interval> ans{intervals[0]};
        for (int i = 1; i < intervals.size(); ++i) {
            if (ans.back().end < intervals[i].start) {
                ans.push_back(intervals[i]);
            } else {
                ans.back().end = max(ans.back().end, intervals[i].end);
            }
        }   
        return ans;
    }
};

　　那个 $sort$ 排序没见过 看了题解会写的 记上一笔！！！！总是会看到很多没见过的有点好玩的东西 emmmm 还不是自己太菜了 o(╥﹏╥)o