Compute Quantile

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

public class Quantile {

　　

Scanner sc = new Scanner(System.in);
String s = null;
while (sc.hasNext()) {
s = sc.nextLine();
System.out.println(s);
}

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int[][] a = {{5, 2}, {7, 2}, {6, 2}};
        int[][] b = {{2, 1000}, {4, 100}, {3, 1000}};
        int[][] c = {{2, 1}, {3, 2}, {5, 3}, {6, 1}, {8, 1}, {11, 1}, {12, 1}, {15, 2}, {18, 2}, {19, 1}};
        int[][] d = {{1, 1,}, {2, 3}, {3, 1}};        

        Quantile e = new Quantile();
        int[] ret = e.computeQuantiles(a, 3, 3);
        System.out.println(Arrays.toString(ret));        
        
        ret = e.computeQuantiles(d, 2, 3);
        System.out.println(Arrays.toString(ret));
    
        ret = e.computeQuantiles(b, 3, 3);
        System.out.println(Arrays.toString(ret));
        
        
        ret = e.computeQuantiles(c, 5, 10);
        System.out.println(Arrays.toString(ret));
    }

    private int[] computeQuantiles(int[][] nums, int Q, int M) {
        Pair[] pairs = new Pair[M];
        int[] quant = new int[Q - 1];
        int N = 0;
        for (int i = 0; i < M; i++) {
            pairs[i] = new Pair(nums[i][0], nums[i][1]);
            N += nums[i][1];
        }
        Arrays.sort(pairs, new Comparator<Pair>(){
            @Override
            public int compare(Pair a, Pair b) {
                return a.val - b.val;
            }
        });
        int quantIndex = 0;
        int numIndex = 0;
        for (int i = 0; i < Q - 1; i++) {
            quant[i] = (i + 1) * N / Q;
        }
        for (Pair pair : pairs) {
            numIndex += pair.count;
            while (quantIndex < Q - 1 && quant[quantIndex] <= numIndex) {
                quant[quantIndex] = pair.val;
                quantIndex++;
            }
        }
        return quant;
    }

}

class Pair {
    int val;
    int count;
    public Pair(int val, int count) {
        this.val = val;
        this.count = count;
    }
}