python - 假定一个值作为初始值，在循环中更新它的值

Question

我正在学习选择排序算法

from typing import List
def find_smallest(arr:List) -> int:
    smallest = arr[0] #set pivot
    smallest_index = 0
    for i in range(1, len(arr)):
        if arr[i] < smallest:
            smallest = arr[i]
            smallest_index = i
    return smallest_index

def selection_sort(arr) -> List:
    new_arr = []
    for i in range(len(arr)):
        smallest = find_smallest(arr)
        new_arr.append(arr.pop(smallest))
    return new_arr

我对函数find_smallest很好奇，
它首先假定 arr[0] 为最小值并启动循环。

我知道完整的代码叫做选择排序算法，

在循环中假设和更新它的值怎么样，有没有术语？

Answer 1

我认为 冒泡排序 就是答案。在我看到你的问题之前，我从未将 bubble loop 视为最小的假设:D

def sort(arr):
    for i in range(len(arr)):
        # we presume a[i] is the smallest one. Then we update by compare it with the rest of the list
        for j in range(i + 1, len(arr)):
            if arr[i] > arr[j]: # if our assumption is wrong (arr[i] is not the smallest), update it with arr[j] (which is smaller than arr[i])
                swap(arr[i], arr[j])

        # After this `for j` loop, arr[i] will be the smallest value of the list