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- import smtplib
- from email.mime.text import MIMEText
- from email.header import Header
- """
- 回溯算法(试探法)
- 在搜索尝试过程中寻找问题的解,当发现已不满足求解条件时,就“回溯”返回,尝试别的路径。回溯法是一种选优搜索法,按选优条件向前搜索,以达到目标。但当探索到某一步时,发现原先选择并不优或达不到目标,就退回一步重新选择,这种走不通就退回再走的技术为回溯法,而满足回溯条件的某个状态的点称为“回溯点”。
- 回溯算法解决问题的
- 针对所给问题,定义问题的解空间,它至少包含问题的一个(最优)解。
- 确定易于搜索的解空间结构,使得能用回溯法方便地搜索整个解空间 。
- 以深度优先的方式搜索解空间,并且在搜索过程中用剪枝函数避免无效搜索。
- """
- class StockTest(object):
- """
- 栈练习
- """
- def queen(self, A, cur=0):
- """
- 八皇后问题
- :param A:
- :param cur:
- :return:
- """
- if cur == len(A):
- print(A)
- # return 0
- else:
- for col in range(len(A)):
- A[cur], flag = col, True
- # 判断当前与之前的所有是否规则冲突
- for row in range(cur):
- if A[row] == col or abs(col - A[row]) == cur - row:
- flag = False
- break
- if flag:
- self.queen(A, cur + 1)
- def movingCount(self, threshold, rows, cols):
- "产生 0 矩阵 "
- board = [[0 for i in range(cols)] for j in range(rows)]
- global acc
- acc = 0
- "下标之和,若大于threshold则TRUE,否则Folse"
- def block(r, c):
- s = sum(map(int, str(r) + str(c)))
- return s > threshold
- def traverse(r, c):
- global acc
- if not (0 <= r < rows and 0 <= c < cols): # 超出角标范围挑出
- return
- if board[r][c] != 0: # 不等于0 跳出
- return
- if board[r][c] == -1 or block(r, c):
- board[r][c] = -1 # 超出门限的点记录-1
- return
- board[r][c] = 1 # 符合规定的点记录1,并计数加一
- acc += 1
- traverse(r + 1, c)
- traverse(r - 1, c)
- traverse(r, c + 1)
- traverse(r, c - 1)
- traverse(0, 0)
- return acc
- def bubble_sort(self, numbers):
- """
- 时间复杂度:O(n^2)
- :param numbers:
- :return:
- """
- n = len(numbers)
- for i in range(n):
- for j in range(0, n - i - 1):
- if numbers[j] > numbers[j + 1]:
- numbers[j], numbers[j + 1] = numbers[j + 1], numbers[j]
- return numbers
- def choose_sort(self, numbers):
- """
- 选择排序,时间复杂度O(n^2)
- :param numbers:
- :return:
- """
- n = len(numbers)
- for i in range(n):
- min_index = i
- min_value = numbers[i]
- for j in range(i + 1, n):
- if min_value > numbers[j]:
- min_value = numbers[j]
- min_index = j
- if min_index != i:
- numbers[min_index] = numbers[i]
- numbers[i] = min_value
- return numbers
- def insert_sort(self, numbers):
- """
- 插入排序,时间复杂度O(n^2)
- :return:
- """
- n = len(numbers)
- for i in range(1, n):
- insert_index = i - 1
- insert_value = numbers[i]
- while insert_index >= 0 and insert_value < numbers[insert_index]:
- numbers[insert_index + 1] = numbers[insert_index]
- insert_index -= 1
- if insert_index + 1 != i:
- numbers[insert_index + 1] = insert_value
- return numbers
- def shell_sort(self, numbers):
- """
- 希尔排序,时间复杂度O(n^2)
- :param numbers:
- :return:
- """
- n = len(numbers)
- gap = int(n / 2)
- while gap > 0:
- for i in range(gap, n):
- temp = numbers[i]
- j = i
- while j >= gap and numbers[j - gap] > temp:
- numbers[j] = numbers[j - gap]
- j -= gap
- numbers[i] = temp
- gap = int(gap / 2)
- return numbers
- def quick_sort(self, numbers):
- """
- 快速排序,时间复杂度O(n^2)
- :param numbers:
- :return:
- """
- if len(numbers) <= 1:
- return numbers
- pivot = numbers[int(len(numbers) / 2)]
- left = [x for x in numbers if x < pivot]
- middle = [pivot]
- right = [x for x in numbers if x > pivot]
- return self.quick_sort(left) + middle + self.quick_sort(right)
- def merge_sort(self, numbers):
- """
- 归并排序
- :param numbers:
- :return:
- """
- pass
- def radix_sort(self, numbers):
- """
- 基数排序,时间复杂度O(n*k)
- :param number:
- :return:
- """
- # 记录当前正在排拿一位,最低位为1
- i = 0
- max_num = max(numbers)
- # 记录最大值的位数
- j = len(str(max_num))
- while i < j:
- # 初始化桶数组
- bucket_list = [[] for _ in range(10)]
- for x in numbers:
- # 找到位置放入桶数组
- bucket_list[int(x / (10 ** i)) % 10].append(x)
- numbers.clear()
- # 放回原序列
- for x in bucket_list:
- numbers.extend([a for a in x])
- i += 1
- return numbers
- def send_mail(self):
- sender = '1285211525@qq.com'
- receivers = '1285211525@qq.com'
- message = MIMEText('Python 邮件发送测试...', 'plain', 'utf-8')
- message['From'] = Header('binren')
- message['To'] = Header('zhangbr')
- subject = 'test mail'
- message['Subject'] = Header(subject, 'utf-8')
- try:
- stmp_obj = smtplib.SMTP('localhost')
- stmp_obj.sendmail(sender, receivers, message.as_string())
- print('send successful')
- except Exception as e:
- print(e)
- if __name__ == '__main__':
- st = StockTest()
- nums = [1, 2, 5, 3, 1, 101, 10, 1111, 2]
- print(st.send_mail())
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