406. Queue Reconstruction by Height

I don't have clue to solve the problem in first place. I followed the top rated solution.
- sort the array by the height in descending order and if heights are the same then sort by the k number in ascending order.
- create an empty array and insert into kth position the sorted people one by one.

1:  class Solution {  
2:  public:  
3:    vector<pair<int, int>> reconstructQueue(vector<pair<int, int>>& people) {  
4:      auto comp = [](pair<int, int> &p1, pair<int, int> &p2) {  
5:        return (p1.first > p2.first) || (p1.first == p2.first && p1.second < p2.second);  
6:      };  
7:      sort(people.begin(), people.end(), comp);  
8:      vector<pair<int, int>> res;  
9:      for (auto p : people) {  
10:        res.insert(res.begin() + p.second, p);  
11:      }  
12:      return res;  
13:    }  
14:  };