排序算法第二讲 --- 选择排序(Python、C++、C)

淩亂°似流年 2023-02-23 05:08 6阅读 0赞

**排序算法系列目录**

[排序算法第一讲 — 冒泡排序(Python、C++、C)][_ _Python_C_C]  
  [排序算法第二讲 — 选择排序(Python、C++、C)][_ _Python_C_C 1]  
  [排序算法第三讲 — 插入排序(Python、C++、C)][_ _Python_C_C 2]  
  [排序算法第四讲 — 快速排序(Python、C++、C)][_ _Python_C_C 3]  
  [排序算法第五讲 — 希尔排序(Python、C++、C)][_ _Python_C_C 4]  
  [排序算法第六讲 — 归并排序(Python、C++、C)][_ _Python_C_C 5]

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**题目描述：**

给你一个整数数组 nums，请你将该数组采用选择排序方式进行升序排列。  
![image][]

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**解题思路:**

选择排序的工作原理：首先在未排序序列中找到最小（大）元素，存放到排序序列的起始位置，然后，再从剩余未排序元素中继续寻找最小（大）元素，然后放到已排序序列的末尾。以此类推，直到所有元素均排序完毕。

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**代码：**

Python写法：

class Solution(object):
        def solution(self,  nums):
            n = len(nums)
            j = 0
            for i in range(n):
                j = i
                for j in range(n-i-1):
                    if nums[j] > nums[j+1]:
                        temp = nums[j]
                        nums[j] = nums[j+1]
                        nums[j+1] = temp
            return nums

上面的这个代码，看起来实在是别扭。原因有两点：1. 变量指代不清 2. 逻辑关系不明

import random
    def choice(nums):
        for i in range(len(nums)-1):
            for j in range(i+1, len(nums)):
                if nums[i] > nums[j]:
                    nums[i], nums[j] = nums[j], nums[i]
        return nums
    
    nums = [random.randint(0, 10) for i in range(10)]
    print(nums)
    print(choice(nums))

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C++写法：

#include<iostream>
    using namespace std;
    
    void swap(int *a, int *b); //交换两个数
    
    int main()
    {
        
    	int  str[5];
    	int  i, j;
    	for (i = 0; i < 5; i++)
    		cin >> str[i];
    
    	for (i = 0; i < 5; i++)
    	{
        
    		j = i;
    		for (j = 0; j < 5 - i - 1; j++)
    		{
        
    			if (str[j] > str[j + 1])
    			{
        
    				swap(&str[j], &str[j + 1]);
    			}
    		}
    	}
    
    	for (i = 0; i < 5; i++)
    		cout << str[i] <<" ";
    	printf("\n");
    	
    	return  0;
    }
    
    void swap(int *a, int *b)
    {
        
    	int c;
    	 c = *a;
    	*a = *b;
    	*b =  c;
    }

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C语言：

#include <stdio.h>
    void swap(int *a, int *b); //交换两个数
    
    int main()
    {
        
    	int  str[5];
    	int  i, j;
    	for (i = 0; i < 5; i++)
    		scanf("%d", &str[i]);
    
    	for (i = 0; i < 5; i++)
    	{
        
    		j = i;
    		for (j = 0; j < 5 - i - 1; j++)
    		{
        
    			if (str[j] > str[j + 1])
    			{
        
    				swap(&str[j], &str[j + 1]);
    			}
    		}
    	}
    
    	for (i = 0; i < 5; i++)
    		printf("%d ", str[i]);
    	printf("\n");
    	
    	return  0;
    }
    
    void swap(int *a, int *b)
    {
        
    	int c;
    	 c = *a;
    	*a = *b;
    	*b =  c;
    }

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**题目来源：**

[http://lab.csdn.net/\#/question/38?tagId=16][http_lab.csdn.net_question_38_tagId_16]

[_ _Python_C_C]: https://blog.csdn.net/weixin_43283397/article/details/107119915
[_ _Python_C_C 1]: https://blog.csdn.net/weixin_43283397/article/details/107139196
[_ _Python_C_C 2]: https://blog.csdn.net/weixin_43283397/article/details/107146712
[_ _Python_C_C 3]: https://blog.csdn.net/weixin_43283397/article/details/107160931
[_ _Python_C_C 4]: https://blog.csdn.net/weixin_43283397/article/details/107242305
[_ _Python_C_C 5]: https://blog.csdn.net/weixin_43283397/article/details/107246548
[image]: https://img-blog.csdnimg.cn/20200529105544672.gif
[http_lab.csdn.net_question_38_tagId_16]: http://lab.csdn.net/#/question/38?tagId=16