Queue Reconstruction by Height

You are given an array of people, people, which are the attributes of some people in a queue (not necessarily in order). Each people[i] = [hi, ki] represents the ith person of height hi with exactly ki other people in front who have a height greater than or equal to hi.
Reconstruct and return the queue that is represented by the input array people. The returned queue should be formatted as an array queue, where queue[j] = [hj, kj] are the attributes of the jth person in the queue (queue[0] is the person at the front of the queue).

Example 1:

Input: people = [[7,0],[4,4],[7,1],[5,0],[6,1],[5,2]]
Output: [[5,0],[7,0],[5,2],[6,1],[4,4],[7,1]]

Approach

Java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class QueueReconstructionByHeight {
    public static void main(String[] args) {
        int people[][] = { { 7, 0 }, { 4, 4 }, { 7, 1 }, 
                    { 5, 0 }, { 6, 1 }, { 5, 2 } };
        int rec[][] = reconstructQueue(people);
        System.out.println(Arrays.deepToString(rec));
    }

    // function to reconstruct the queue
    static int[][] reconstructQueue(int[][] people) {
        // sort array based on condition
        Arrays.sort(people, new Comparator<int[]>() {
            @Override
            public int compare(int[] a, int[] b) {
                if (a[0] == b[0])
                    if (a[1] < b[1])
                        return -1;
                    else
                        return 1;
                else if (a[0] > b[0])
                    return -1;
                else
                    return 1;
            }
        });

        List<int[]> res = new ArrayList<int[]>();
        if (people.length == 0)
            return null;

        // add all elemnt in result
        for (int i = 0; i < people.length; i++) {
            res.add(people[i][1], people[i]);
        }
        // convert list to 2d array
        int a[][] = new int[people.length][2];
        for (int i = 0; i < res.size(); i++) {
            a[i] = res.get(i);
        }
        return a;
    }
}

C++

#include <bits/stdc++.h>
using namespace std;

//comparator used to sort the array
static bool cmp(vector<int> a ,vector<int> b)
{
        if(a[0]==b[0])
              return a[1]<b[1];
        else
            return a[0]>b[0];
}

//function to reconstruct the queue
vector<vector<int>> reconstructQueue(vector<vector<int>>& people)
{
        sort(people.begin(),people.end(),cmp);
        vector<vector<int>> res;
       if(people.size()==0)
            return res;
        for(int i=0;i<people.size();i++)
              res.insert(res.begin()+people[i][1],people[i]);
        return res;
}

int main()
{
    vector<vector<int>> people ={{7,0},{4,4},{7,1},
                                {5,0},{6,1},{5,2}};
    people=reconstructQueue(people);
    cout<<"[";
    for(int i=0;i<people.size();i++)
      {
          
          cout<<"["<<people[i][0]<<" "<<people[i][1]<<"]";
          if(i!=people.size()-1)
            cout<<",";
      }
      cout<<"]";
      return 0;
}