挑战程序设计竞赛（算法和数据结构）——7.4计数排序（桶排序）的JAVA实现

Posted 2021-12-15 小乖乖的臭坏坏

原理：

可以参照以下视频，看10分钟就会了~

https://www.bilibili.com/video/BV1wK4y1M7EU?from=search&seid=2666668376189241744&spm_id_from=333.337.0.0

import java.io.BufferedInputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Scanner;

public class BucketSort_CountingSort 
    public static void main(String[] args) 
        Scanner cin = new Scanner(new BufferedInputStream(System.in));
        int n = cin.nextInt();
        int[] A = new int[n];
        for (int i=0;i<n;i++)
            A[i] = cin.nextInt();
        
        ArrayList B = bucketSort(A, n);

        Iterator<Integer> it = B.iterator();
        while(it.hasNext())
            int element = it.next();
            System.out.print(element + ", ");
        
    

    //默认A和B是从1开始索引，到n结束，因此下标A，B应该有n+1个元素
    public static ArrayList<Integer> bucketSort(int[] A, int k)
        ArrayList<Integer> B = new ArrayList<Integer>();
        int[] C = new int[k+1];
        int n = A.length;
        for (int i =0;i<n;i++)
            C[A[i]]++;
        
        for(int i=0;i<=k;i++)
            while(C[i]!=0)
                B.add(i);
                C[i]--;
            
        
        return B;
    

输入：

7
2 5 1 3 2 3 0

输出：

0, 1, 2, 2, 3, 3, 5,