lc 合并区间

链接：https://leetcode-cn.com/problems/merge-intervals/

代码：

class Solution {
public:
    // [[2,3],[4,5],[6,7],[8,9],[1,10]]
    static bool myfunc(vector<int> i1, vector<int> i2) {
        return i1[0] < i2[0];
    }
    vector<vector<int>> merge(vector<vector<int>>& intervals) {
        int n = intervals.size();
        vector<vector<int>> res = {};
        if(n == 0) return {};
        sort(intervals.begin(), intervals.end(), myfunc);
        
        for(int i = 0; i < n; i++) {
            int last = res.size()-1;
            if(res.size() == 0 || res[last][1]< intervals[i][0]) {
                res.push_back(intervals[i]);
            }
            else {
                res[last][1] = max(res[last][1], intervals[i][1]);
            }
        }
        return res;
    }
};

思路：想要不重复的话就必须要排序，如何做到不重不漏？