参考代码：

# 用装饰实现
def singleton(cls):
    instances = {}
    def wrapper(*args, **kwargs):
        if cls not in instances:
            instances[cls] = cls(*args, **kwargs)
        return instances[cls]
    return wrapper


@singleton
class Foo(object):
    pass
foo1 = Foo()
foo2 = Foo()
print(foo1 is foo2)

# 用基类实现
class Singleton(object):
    def __new__(cls, *args, **kwargs):
        if not hasattr(cls, '_instance'):
            cls._instance = super(Singleton, cls).__new__(cls, *args, **kwargs)
        return cls._instance

class Foo(Singleton):
    pass
foo1 = Foo()
foo2 = Foo()
print(foo1 is foo2)

# 使用元类实现
class Singleton(type):
    def __call__(cls, *args, **kwargs):
        if not hasattr(cls, '_instance'):
            cls._instance = super(Singleton, cls).__call__(*args, **kwargs)
        return cls._instance

# Python2
class Foo(object):
    __metaclass__ = Singleton
# Python3
class Foo(metaclass=Singleton):
    pass

foo1 = Foo()
foo2 = Foo()
print(foo1 is foo2)

参考代码：

def sortport():
  for i in range(len(l)-1):
    for j in range(len(l)-1-i):
      if l[j] > l[j+1]:
        l[j],l[j+1] = l[j+1],l[j]
   return l

参考代码：

def binary_search(data, item):
    n = len(data)
    if n > 0:
        mid = n // 2
        if data[mid] == item:
            return True
        elif data[mid] > item:
            return binary_search(data[:mid], item)
        else:
            return binary_search(data[mid+1:], item)
    return False

参考代码：

class Solution:
    def secondMax(self, nums):
        maxValue = max(nums[0], nums[1])
        secValue = min(nums[0], nums[1])
        for i in range[2, len(nums)]:
            if nums[i] > maxValue:
                secValue = maxValue
                maxValue = nums[i]
            elif nums[i] > secValue:
                secValue = nums[i]
        return secValue

参考代码：

raw=[]
for i in range(3):
    x=int(input('int%d: '%(i)))
    raw.append(x)

for i in range(len(raw)):
    for j in range(i,len(raw)):
        if raw[i]>raw[j]:
            raw[i],raw[j]=raw[j],raw[i]

参考代码：

import numpy as np

#方法 1
def fib_matrix(n):
    for i in range(n):
        res = pow((np.matrix([[1, 1], [1, 0]], dtype='int64')), i) * np.matrix([[1], [0]])
        print(int(res[0][0]))
# 调用
fib_matrix(50)

#方法 2
# 使用矩阵计算斐波那契数列
def Fibonacci_Matrix_tool(n):
    Matrix = np.matrix("1 1;1 0", dtype='int64')
    # 返回是matrix类型
    return np.linalg.matrix_power(Matrix, n)

def Fibonacci_Matrix(n):
    result_list = []
    for i in range(0, n):
        result_list.append(np.array(Fibonacci_Matrix_tool(i))[0][0])
    return result_list

参考代码：

class Solution:
    def rotateString(self, s, offset):
        if len(s) > 0:
            offset = offset % len(s)
        temp = (s + s)[len(s) - offset : 2 * len(s) - offset]
        for i in range(len(temp)):
            s[i] = temp[i]

参考代码：

class Solution:
    def reverseInteger(self, number):
        h = int(number/100)
        t = int(number%100/10)
        z = int(number%10)
        return (100*z + 10*t + h)

参考代码：

class Solution:
    def canGetString(self, s, t):
        pos = 0
        for x in t:
            while pos < len(s) and s[pos] != x:
                pos += 1
            if pos == len(s):
                return False
            pos += 1
        return True

参考代码：

# 方法1
ip = input("请输入IP:")
if len(ip.split(".")) !=4:
    print("NO")
    exit()
elif " " in ip.split("."):
    print("NO")
    exit()
else:
    new_list = [int(i) for i in ip.split(".")]
    for i in new_list:
        if not 0 <= i < 255:
            print("NO")
            break
    else:
        print("YES")

# 方法2
import IPy 
def is_ip(address): 
  try: 
    IPy.IP(address) 
    return "YES"
  except Exception as e: 
    return "NO"
address = input("请输入IP:")
is_ip(address)

参考代码:

from math import ceil
def divide_iter(lst, n):
    if n <= 0:
        yield lst
        return
    i, div = 0, ceil(len(lst) / n)
    while i < n:
        yield lst[i * div: (i + 1) * div]
        i += 1
list(divide_iter([1, 2, 3, 4, 5], 2))

参考代码：

class Solution:
    def theTwoNumbers(self, a):
        ans = [0, 0]
        for i in a:
            ans[0] = ans[0] ^ i
        c = 1
        while c & ans[0] != c:
            c = c << 1
        for i in a:
            if i & c == c:
                ans[1] = ans[1] ^ i
        ans[0] = ans[0] ^ ans[1]
        return ans

参考代码：

input_str = input()
dimensions=[int(x) for x in input_str.split(',')]
rowNum=dimensions[0]
colNum=dimensions[1]
multilist = [[0 for col in range(colNum)] for row in range(rowNum)]

for row in range(rowNum):
    for col in range(colNum):
        multilist[row][col]= row*col

print(multilist)

参考代码：

class Solution:
    def mergeSortedArray(self, A, B):
        i, j = 0, 0 
        C = []
        while i < len(A) and j < len(B):
            if A[i] < B[j]:
                C.append(A[i])
                i += 1
            else:
                C.append(B[j])
                j += 1
        while i < len(A):
            C.append(A[i])
            i += 1
        while j < len(B):
            C.append(B[j])
            j += 1
        return C

可以尝试抽象一下。