【LeetCode热题100】【普通数组】合并区间

class Solution {
public:
    vector<vector<int>> merge(vector<vector<int>>& intervals) {
        vector<vector<int>>ans;
        std::sort(intervals.begin(),intervals.end());
        for(auto&one:intervals){
            if(ans.empty()||ans.back()[1]<one[0]) // 空或者可以不能合并
                ans.push_back(one);
            else
                ans.back()[1]=max(ans.back()[1],one[1]); // 合并
        }
        return ans;
    }
};