Problem : Given a string of opening and closing parentheses, check whether it’s balanced. We have 3 types of parentheses: round brackets: (), square brackets: [], and curly brackets: {}. Assume that the string doesn’t contain any other character than these, no spaces words or numbers. As a reminder, balanced parentheses require every opening parenthesis … Continue reading Balanced Parentheses Check | Python

# Category: Data Structures

# Find the largest continuous sum | Python

Problem : Given an array of integers(positive and neg), Find the largest continuous sum . Solution : def large_cont_sum(arr): if len(arr) < 1 : return 0 max_sum = current_sum = arr[0] for num in arr[1:]: current_sum = max(num,current_sum+num) max_sum = max(current_sum,max_sum) print max_sum large_cont_sum([1,2,-1,3,4,10,10,-10,-1]) #29

# Linked List Nth to Last Node | Python

Problem : Function that takes a head node and an integer value n and then returns the nth to last node in the linked list. Solution : class Node: def __init__(self, value): self.value = value self.nextnode = None def nth_to_last_node(n, head): node = head nodes = [] while node != None: nodes.append(node) node = node.nextnode return nodes[-n]

# Binary Search | Python

Binary Search implementation in Python def binary_search(arr,ele): """ binary_search works only on sorted array, also it follows divide and conquer fundamentals """ first = 0 last = len(arr) - 1 # as indexing starts at 0 found = False while first <= last and not found: mid = (first+last)/2 # to get mid point of … Continue reading Binary Search | Python

# Reverse Linked List | Python

class Node(object): def __init__(self,value): self.value = value self.nextnode = None def reverse(head): # Set up current,previous, and next nodes current = head previous = None nextnode = None # until we have gone through to the end of the list while current: nextnode = current.nextnode # Reverse the pointer ot the next_node current.nextnode = previous … Continue reading Reverse Linked List | Python

# Doubly Linked List | Python

Implementation of Doubly Linked List in Python class DoublyLinkedList(object): def __init__(self,val): self.value = val self.next_node = None self.prev_node = None a = DoublyLinkedList(1) b = DoublyLinkedList(2) c = DoublyLinkedList(3) a.next_node = b b.prev_node = a b.next_node = c c.prev_node = b

# Singly Linked Lists | Python

Implementation of singly linked lists in Python. class Node(object): def __init__(self,val): self.value = val self.nextNode = Node a = Node(1) b = Node(2) c = Node(3) a.nextNode = b b.nextNode = c print a.nextNode.value