如何避免二维数组重复数字？ Bingo卡生成器代码排重求助

你的代码目前的问题是：生成随机数字时没有校验当前行内是否已存在该数字，导致同一行出现重复的1-90范围内的数值。以下是修改后的代码，确保每行包含4个0和5个互不重复的随机数：

方案一：用Set跟踪已生成的数字 #

import java.util.Random;
import java.util.HashSet;
import java.util.Set;

public class BingoCardGenerator {

    public static Integer[][] generateBingoCard() {
        int numRows = 3;
        int numCols = 9;
        int randomNumbersPerRow = 5;
        int randomNumberBound = 90;
    
        Random random = new Random();
        Integer[][] bingoCard = new Integer[numRows][numCols];
        
        for (int row = 0; row < numRows; row++) {
            // 初始化当前行为0
            for (int col = 0; col < numCols; col++) {
                bingoCard[row][col] = 0;
            }
            
            Set<Integer> usedNumbers = new HashSet<>();
            int assignedCount = 0;
            
            while (assignedCount < randomNumbersPerRow) {
                // 随机选一个未被赋值的列
                int indexToAssign = random.nextInt(numCols);
                if (bingoCard[row][indexToAssign] != 0) {
                    continue;
                }
                
                // 生成不重复的随机数
                int numToAssign;
                do {
                    numToAssign = random.nextInt(randomNumberBound) + 1;
                } while (usedNumbers.contains(numToAssign));
                
                bingoCard[row][indexToAssign] = numToAssign;
                usedNumbers.add(numToAssign);
                assignedCount++;
            }
        }
    
        // 打印卡片
        for (int row = 0; row < numRows; row++) {
            for (int col = 0; col < numCols; col++) {
                System.out.printf("%2d ", bingoCard[row][col]);
            }
            System.out.println();
        }
        return bingoCard;
    }
    
    public static void main(String[] args) {
        generateBingoCard();
    }
}

关键改动： #

• 每行新增Set<Integer> usedNumbers，用于记录当前行已生成的随机数，避免重复
• 生成数字时通过do-while循环确保新数字不在usedNumbers中
• 用assignedCount跟踪已成功赋值的数字数量，确保每行刚好生成5个不重复数

方案二：先生成不重复随机数集合再分配 #

这种方式效率更高，适合范围较大的场景：

import java.util.Random;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class BingoCardGenerator {

    public static Integer[][] generateBingoCard() {
        int numRows = 3;
        int numCols = 9;
        int randomNumbersPerRow = 5;
        int randomNumberBound = 90;
    
        Random random = new Random();
        Integer[][] bingoCard = new Integer[numRows][numCols];
        
        for (int row = 0; row < numRows; row++) {
            // 初始化当前行为0
            for (int col = 0; col < numCols; col++) {
                bingoCard[row][col] = 0;
            }
            
            // 生成1-90的列表并打乱
            List<Integer> numbers = new ArrayList<>();
            for (int i = 1; i <= randomNumberBound; i++) {
                numbers.add(i);
            }
            Collections.shuffle(numbers, random);
            
            // 随机选5个不同的列
            List<Integer> cols = new ArrayList<>();
            for (int i = 0; i < numCols; i++) {
                cols.add(i);
            }
            Collections.shuffle(cols, random);
            
            // 给选中的列赋值不重复的随机数
            for (int i = 0; i < randomNumbersPerRow; i++) {
                int colIndex = cols.get(i);
                bingoCard[row][colIndex] = numbers.get(i);
            }
        }
    
        // 打印卡片
        for (int row = 0; row < numRows; row++) {
            for (int col = 0; col < numCols; col++) {
                System.out.printf("%2d ", bingoCard[row][col]);
            }
            System.out.println();
        }
        return bingoCard;
    }
    
    public static void main(String[] args) {
        generateBingoCard();
    }
}

关键改动： #

• 每行先创建1-90的完整列表，打乱后取前5个，天然保证不重复
• 同时创建列索引列表并打乱，取前5个列来赋值，确保列不重复
• 避免了循环校验的开销，逻辑更清晰

内容的提问来源于stack exchange，提问作者Daniel Requena