algorithms-MergeSorted-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_41672628/article/details/80394928

本文介绍了一种使用Java实现的归并排序算法。通过随机生成的整数数组演示了排序过程，并验证了排序算法的有效性。文章详细展示了归并排序的递归分解与合并过程。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

package algorithms;

import java.util.Arrays;
import java.util.Random;

public class MergeSorted {
	public static void main(String[] args) {
		int[] nums = new int[10];
		Random rand = new Random();
		for (int i = 0; i < 10; i++) {
			nums[i] = rand.nextInt(100);
		}
		System.out.println(Arrays.toString(nums));
		int[] sort = mergesort(nums, 0, nums.length - 1);
		
		System.out.println(Arrays.toString(sort));
		System.out.println(Arrays.equals(sort,nums));
		
	}

	public static int[] mergesort(int[] nums, int start, int end) {
		if (start >= end) {
			//重点易错
			return new int[] { nums[start] };
		}
		int mid = (start + end) / 2;
		int[] i1 = mergesort(nums, start, mid);
		int[] i2 = mergesort(nums, mid + 1, end);
		return merge(i1, i2);
	}

	public static int[] merge(int[] num1, int[] num2) {
		int[] nums = new int[num1.length + num2.length];
		int n1 = 0, n2 = 0, i = 0;
		//易错,判断条件是这个
		while (n1 != num1.length && n2 != num2.length) {
			if (num1[n1] <= num2[n2]) {
				nums[i] = num1[n1];
				n1++;
				i++;
			} else {
				nums[i] = num2[n2];
				n2++;
				i++;
			}
		}
		if (n1 == num1.length) {
			System.arraycopy(num2,n2,nums,i,num2.length-n2);
		}else{
			System.arraycopy(num1,n1,nums,i,num1.length-n1);
		}
		return nums;
	}
}