QueueReconstructionByHeight406.java

/**
 * 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.
 *
 * Note:
 * The number of people is less than 1,100.
 *
 *
 * Example
 *
 * Input:
 * [[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]]
 *
 */


public class QueueReconstructionByHeight406 {
    public int[][] reconstructQueue(int[][] people) {
        int y = people.length;
        if (y == 0) return people;

        Arrays.sort(people, new SortRule());

        LinkedList<int[]> res = new LinkedList<>();
        for(int[] p: people){
            res.add(p[1], p);
        }

        return res.toArray(new int[people.length][]);
    }

    class SortRule implements Comparator<int[]> {
        @Override
        public int compare(int[] a, int[] b) {
            int diff = a[0] - b[0];
            if (diff < 0) return 1;
            else if (diff > 0) return -1;
            else return a[1] - b[1];
        }
    }
}