【Java】矩阵按列排序（随机/指定列）

源码如下：

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

public class DuoTiaoJianPaiXu {
    public static void main(String[] args) {
        int x = 5;
        int y = 6;
        int[][] arrs = getArrs(x, y);
        out(arrs);
        int[] cols = getAndOutCols(y);
        ArrayList<List<Node>> lists = getLists(x, y);
        sort(arrs, lists, cols);
        int[][] ans = getAns(x, y, arrs, lists);
        out(ans);
    }

    private static int[][] getArrs(int x, int y) {
        int[][] arrs = new int[x][y];
        for (int i = 0; i < x; i++) {
            for (int j = 0; j < y; j++) {
                arrs[i][j] = (int) (Math.random() * Math.max(10, x * y));
            }
        }
        return arrs;
    }

    private static void out(int[][] arrs) {
        for (int[] arr : arrs) {
            for (int a : arr) {
                System.out.print(a + "\t");
            }
            System.out.println();
        }
    }

    private static int[] getAndOutCols(int y) {
        int[] cols = new int[y];
        HashSet<Integer> set = new HashSet<>();
        for (int i = 0; i < y; i++) {
            int num = -1;
            do {
                num = (int) (Math.random() * y);
            } while (set.contains(num));
            set.add(num);
            cols[i] = num;
            System.out.print(cols[i] + "\t");
        }
        System.out.println();
        return cols;
    }

    private static void sort(int[][] arrs, ArrayList<List<Node>> lists, int[] cols) {
        for (List<Node> list : lists) {
            list.sort((node1, node2) -> {
                if (node1.y != node2.y) {
                    System.out.println("y1 =" + node1.y + " , y2 = " + node2.y);
                    return 0;
                }
                int befor = -1;
                for (int col : cols) {
                    if (befor == -1 || arrs[node1.x][befor] == arrs[node2.x][befor]) {
                        befor = col;
                        continue;
                    }
                    return arrs[node1.x][befor] - arrs[node2.x][befor];
                }
                return arrs[node1.x][node1.y] - arrs[node2.x][node2.y];
            });
        }
    }

    private static int[][] getAns(int x, int y, int[][] arrs, ArrayList<List<Node>> lists) {
        int[][] ans = new int[x][y];
        for (int j = 0; j < y; j++) {
            List<Node> list = lists.get(j);
            for (int i = 0; i < x; i++) {
                Node node = list.get(i);
                ans[i][j] = arrs[node.x][node.y];
            }
        }
        return ans;
    }

    private static ArrayList<List<Node>> getLists(int x, int y) {
        ArrayList<List<Node>> lists = new ArrayList<>();
        for (int j = 0; j < y; j++) {
            ArrayList<Node> list = new ArrayList<>();
            for (int i = 0; i < x; i++) {
                list.add(new Node(i, j));
            }
            lists.add(list);
        }
        return lists;
    }

    private static class Node {
        int x;
        int y;

        public Node(int x, int y) {
            this.x = x;
            this.y = y;
        }
    }
}