面试题与答案

def factorial(n):

  return 1 if n == 0 else n * factorial(n-1)

Example:

def is_prime(num):

  if num < 2:

  return False

  for i in range(2, int(num**0.5) + 1):

    if num % i == 0:

      return False

   return True

Example:

class Stack:

  def __init__(self):

    self.items = []

 

  def push(self, item):

    self.items.append(item)

 

  def pop(self):

    return self.items.pop()

 

  def is_empty(self):

    return len(self.items) == 0

Example:

def fibonacci(n):

  if n <= 1:

    return n

  else:

    return fibonacci(n-1) + fibonacci(n-2)

Example:

def longest_increasing_subsequence(arr):

  n = len(arr)\n lis = [1]*n

  for i in range(1, n):

    for j in range(0, i):

      if arr[i] > arr[j] and lis[i] < lis[j] + 1:

        lis[i] = lis[j] + 1

          return max(lis)

Example:

def power_set(input_set):

  n = len(input_set)

  for i in range(1 << n):

    subset = [input_set[j]

      for j in range(n):

        if (i & (1 << j)) > 0]

          yield subset

Example:

def binary_search(arr, target):

  low, high = 0, len(arr) - 1

  while low <= high:

    mid = (low + high) // 2

    if arr[mid] == target:

      return mid

    elif arr[mid] < target:

      low = mid + 1

    else:

      high = mid - 1

    return -1

Example: