Java归并排序

最新推荐文章于 2022-05-26 15:48:11 发布

原创最新推荐文章于 2022-05-26 15:48:11 发布 · 382 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#Java #排序 #归并

原创专栏收录该内容

4 篇文章

订阅专栏

本文介绍了一种基于归并排序算法的实现方式。通过将输入数组拆分成单个元素，再逐步合并相邻的已排序数组来完成整个排序过程。文章包含完整的Java代码示例，并在主函数中演示了如何对一个整数数组进行排序。

package test;

import java.util.Arrays;

public class MergeSorter {
    
    private int[] sort(int[] in1, int[] in2) {
        
        int[] out = new int[in1.length + in2.length];
        int i = 0, j = 0, k = 0;
        while (i < in1.length && j < in2.length) {
            
           if (in1[i] <= in2[j]) {
               out[k++] = in1[i++];
           } else {
               out[k++] = in2[j++];
           }
        }
        
        for (int t1 = i; t1 < in1.length; t1++) {
            out[k++] = in1[t1];
        }
        for (int t2 = j; t2 < in2.length; t2++) {
            out[k++] = in2[t2];
        }
        return out;
    }
    
    private int[][] merge(int[][] input) {
        
        int len = (int) Math.ceil(input.length / 2.0);
        int[][] output = new int[len][];
        int k = 0;
        for (int i = 0; i < input.length; i+=2) {
            if (i == input.length - 1) {
                output[k++] = input[i];
            } else {
                output[k++] = sort(input[i], input[i+1]);
            }
        }
        return output;
    }
    
    public int[] sort(int[] input) {
        
        int[][] mergeArray = new int[input.length][];
        for (int i = 0; i < input.length; i++) {
            int[] arr = {input[i]};
            mergeArray[i] = arr;
        }
        while (mergeArray.length > 1) {
            mergeArray = merge(mergeArray);
        }
        return mergeArray[0];
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        
        int[] sample = {6, 202, 100, 301, 38, 8, 1, 98, 2, 13, 24, 45};

        MergeSorter tester = new MergeSorter();
        int res[] = tester.sort(sample);
        System.out.println(Arrays.toString(res));
    }
}