Python Coding Interview Questions and Answers

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)

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

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

class TreeNode:
 def __init__(self, value):
 self.value = value
 self.left = None
 self.right = None

def is_balanced(root):
 if root is None:
 return True
 left_height = height(root.left)
 right_height = height(root.right)
 return abs(left_height - right_height) <= 1 and is_balanced(root.left) and is_balanced(root.right)

def height(node):
 if node is None:
 return 0
 return max(height(node.left), height(node.right)) + 1

from collections import OrderedDict

class LRUCache:
 def __init__(self, capacity):
 self.cache = OrderedDict()
 self.capacity = capacity

 def get(self, key):
 if key in self.cache:
 self.cache.move_to_end(key)
 return self.cache[key]
 return -1

 def put(self, key, value):
 if len(self.cache) >= self.capacity:
 self.cache.popitem(last=False)
 self.cache[key] = value
 self.cache.move_to_end(key)