package com.hit.basmath.interview.top_interview_questions.hard_collection.others;

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

/**
 * 406. Queue Reconstruction by Height
 * <p>
 * Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers (h, k), where h is the height of the person and k is the number of people in front of this person who have a height greater than or equal to h. Write an algorithm to reconstruct the queue.
 * <p>
 * Note:
 * <p>
 * The number of people is less than 1,100.
 * <p>
 * Example
 * <p>
 * Input:
 * <p>
 * [[7,0], [4,4], [7,1], [5,0], [6,1], [5,2]]
 * <p>
 * Output:
 * <p>
 * [[5,0], [7,0], [5,2], [6,1], [4,4], [7,1]]
 */
public class _406 {
    public int[][] reconstructQueue(int[][] people) {
        if (people == null || people.length == 0 || people[0].length == 0)
            return new int[0][0];

        Arrays.sort(people, new Comparator<int[]>() {
            public int compare(int[] a, int[] b) {
                if (b[0] == a[0]) return a[1] - b[1];
                return b[0] - a[0];
            }
        });

        int n = people.length;
        ArrayList<int[]> tmp = new ArrayList<>();
        for (int i = 0; i < n; i++)
            tmp.add(people[i][1], new int[]{people[i][0], people[i][1]});

        int[][] res = new int[people.length][2];
        int i = 0;
        for (int[] k : tmp) {
            res[i][0] = k[0];
            res[i++][1] = k[1];
        }

        return res;
    }
}