Add solutions for Python Hack1 - May Cohort

linked_list.py

@@ -0,0 +1,39 @@
+class Node:
+    def _init_(self, data=None):
+        self.data = data
+        self.next = None
+
+class LinkedList:
+    def _init_(self):
+        self.head = None
+
+    def append(self, data):
+        if not self.head:
+            self.head = Node(data)
+        else:
+            current = self.head
+            while current.next:
+                current = current.next
+            current.next = Node(data)
+
+    def find_max(self) -> int:
+        if not self.head:
+            raise ValueError("List is empty")
+
+        max_element = self.head.data
+        current = self.head
+        while current:
+            if current.data > max_element:
+                max_element = current.data
+            current = current.next
+
+        return max_element
+
+# Example usage
+if __name__ == "_main_":
+    ll = LinkedList()
+    ll.append(3)
+    ll.append(1)
+    ll.append(4)
+    ll.append(2)
+    print(ll.find_max())  # Output: 4

main.py

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+from reverse_string import reverse_string
+from queue_with_stacks import QueueWithStacks
+from linked_list import LinkedList
+
+def main():
+    # Task 1: Reverse a String Using a Stack
+    input_str = "hello"
+    output_str = reverse_string(input_str)
+    print(output_str)  # Output: "olleh"
+
+    # Task 2: Implement a Queue Using Two Stacks
+    q = QueueWithStacks()
+    q.enqueue(1)
+    q.enqueue(2)
+    print(q.dequeue())  # Output: 1
+    print(q.dequeue())  # Output: 2
+
+    # Task 3: Find the Maximum Element in a List Using a Linked List
+    ll = LinkedList()
+    ll.append(3)
+    ll.append(1)
+    ll.append(4)
+    ll.append(2)
+    print(ll.find_max())  # Output: 4
+
+if __name__ == "_main_":
+    main()

queue_with_stacks.py

@@ -0,0 +1,22 @@
+class QueueWithStacks:
+    def _init_(self):
+        self.stack1 = []
+        self.stack2 = []
+
+    def enqueue(self, x: int):
+        self.stack1.push(x)
+
+    def dequeue(self) -> int:
+        if self.stack2.is_empty():
+            while not self.stack1.is_empty():
+                self.stack2.push(self.stack1.pop())
+
+        return self.stack2.pop()
+
+# Example usage
+if __name__ == "_main_":
+    q = QueueWithStacks()
+    q.enqueue(1)
+    q.enqueue(2)
+    print(q.dequeue())  # Output: 1
+    print(q.dequeue())  # Output: 2

reverse_string.py

@@ -0,0 +1,32 @@
+class Stack:
+    def _init_(self):
+        self.items = []
+
+    def push(self, item):
+        self.items.append(item)
+
+    def pop(self):
+        if not self.is_empty():
+            return self.items.pop()
+        else:
+            return None
+
+    def is_empty(self):
+        return len(self.items) == 0
+
+def reverse_string(s: str) -> str:
+    stack = Stack()
+    for char in s:
+        stack.push(char)
+
+    reversed_s = ""
+    while not stack.is_empty():
+        reversed_s += stack.pop()
+
+    return reversed_s
+
+# Example usage
+if __name__ == "_main_":
+    input_str = "hello"
+    output_str = reverse_string(input_str)
+    print(output_str)  # Output: "olleh"