review

时间复杂度所耗费的时间从小到大依次是
O(1)< O(logn) < O(n) < O(n*logn) < O(n^2) < O(n^3) < O(2^n) < O(n!) < O(n^n)

斐波那契数列

# encoding=utf-8
def fun(n):
    a, b = 0, 1
    while a < n:
        print(a)
        a, b = b, a+b

if __name__ == '__main__':
    fun(1000)

冒泡排序

时间复杂度O(n^2)

# encoding=utf-8
def bubble_sort(data_list):
    for i in range(len(data_list)-1):  # i代表需要冒泡循环比较的次数
        for j in range(len(data_list)-i-1):  # j代表循环到的下标位置
            if data_list[j] > data_list[j+1]:  # 判断相邻大小，并进行交换
                data_list[j], data_list[j+1] = data_list[j+1], data_list[j]
    return data_list


if __name__ == '__main__':
    a = [10, 17, 50, 7, 30, 24, 27, 45, 15, 5, 36, 21]
    data = bubble_sort(a)
    print(data)

选择排序

时间复杂度O(n^2)

# encoding=utf-8
def select_sort(data_list):
    for i in range(len(data_list)-1):
        min_index = i
        for j in range(i+1, len(data_list)):
            if data_list[j] < data_list[min_index]:
                min_index = j
        if min_index != i:
            data_list[i], data_list[min_index] = data_list[min_index], data_list[i]
    return data_list


if __name__ == '__main__':
    a = [10, 17, 50, 7, 30, 24, 27, 45, 15, 5, 36, 21]
    data = select_sort(a)
    print(data)

插入排序

时间复杂度O(n^2)

# encoding=utf-8
def insert_sort(data_list):
    for i in range(1, len(data_list)):
        for j in range(i, 0, -1):
            if data_list[j] > data_list[j-1]:
                data_list[j], data_list[j-1] = data_list[j-1], data_list[j]
    return data_list


if __name__ == '__main__':
    a = [10, 17, 50, 7, 30, 24, 27, 45, 15, 5, 36, 21]
    data = insert_sort(a)
    print(data)

快速排序

# encoding=utf-8
def quick_sort(data_list, start, end):
    """
    快速排序
    :param data_list: 未排序的list
    :param start: 起始元素下标
    :param end: 结束元素下标
    :return: 排序后的list
    """
    if start >= end:
        return

    mid = data_list[start]

    low = start

    high = end

    while low < high:
        while low < high and data_list[high] >= mid:
            high -= 1
        data_list[low] = data_list[high]

        while low < high and data_list[low] < mid:
            low += 1
        data_list[high] = data_list[low]

    data_list[low] = mid

    quick_sort(data_list, start, low-1)
    quick_sort(data_list, low+1, end)
    return data_list


if __name__ == '__main__':
    a = [10, 17, 50, 7, 30, 24, 27, 45, 15, 5, 36, 21, 20, 21, 21, 3294, 100]
    data = quick_sort(a, 0, len(a)-1)
    print(data)

希尔排序