add stack

Author: mdobydullah

content/2.dsa/1.introduction/_dir.yml

@@ -1,5 +1,4 @@
 title: Introduction
-icon: lucide:pyramid
 navigation.redirect: /dsa/introduction/what-is-dsa
 
 

content/2.dsa/2.data-structures-i/1.stack.md

@@ -0,0 +1,120 @@
+---
+title: Stack
+description: 'Introduction to Data Structures and Algorithms'
+---
+
+A stack is a linear data structure that operates on a Last In, First Out (LIFO) basis, where the last element added is the first one to be removed. It's similar to a stack of plates—only the top plate can be removed at a time. The stack supports two main operations:
+
+1. **Push**: Adds an element to the top of the stack.
+2. **Pop**: Removes the element from the top of the stack.
+
+### Key Properties of Stack
+
+* **LIFO (Last In, First Out)**: The last element added is the first one to be removed.
+* **Top**: A pointer or reference to the element at the top of the stack.
+* **Size**: The number of elements in the stack.
+
+### Basic Operations
+
+* **Push(x)**: Insert element at the top of the stack.
+* **Pop()**: Remove and return the element from the top of the stack.
+* **Peek()** or **Top()**: Return the element at the top without removing it.
+* **isEmpty()**: Check if the stack has any elements.
+* **isFull()**: Check if the stack has reached its maximum capacity (for fixed-size stacks).
+
+### Implementation
+
+Stacks can be implemented using arrays or linked lists.
+
+::code-group
+
+```python [Array]
+# In an array-based stack, elements are added to the endof an array.
+# Here's a simple code example in Python:
+
+class Stack:
+    def __init__(self, capacity):
+        self.stack = []
+        self.capacity = capacity
+
+    def push(self, item):
+        if len(self.stack) < self.capacity:
+            self.stack.append(item)
+        else:
+            print("Stack Overflow")
+
+    def pop(self):
+        if not self.is_empty():
+            return self.stack.pop()
+        else:
+            print("Stack Underflow")
+
+    def peek(self):
+        if not self.is_empty():
+            return self.stack[-1]
+        return None
+
+    def is_empty(self):
+        return len(self.stack) == 0
+
+# Usage example
+s = Stack(5)
+s.push(10)
+s.push(20)
+print(s.pop())  # Output: 20
+```
+
+```python [Linked List]
+# In a linked list-based stack, each element points to the next one,
+# allowing flexible resizing.
+
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+
+class Stack:
+    def __init__(self):
+        self.top = None
+
+    def push(self, item):
+        new_node = Node(item)
+        new_node.next = self.top
+        self.top = new_node
+
+    def pop(self):
+        if self.is_empty():
+            print("Stack Underflow")
+            return None
+        popped_data = self.top.data
+        self.top = self.top.next
+        return popped_data
+
+    def peek(self):
+        return self.top.data if self.top else None
+
+    def is_empty(self):
+        return self.top is None
+
+# Usage example
+s = Stack()
+s.push(10)
+s.push(20)
+print(s.pop())  # Output: 20
+```
+
+::
+
+### Applications of Stack
+
+* **Expression Evaluation**: Evaluating postfix or prefix expressions.
+* **Syntax Parsing**: Parsing expressions in compilers and interpreters.
+* **Backtracking**: Like undo operations in text editors.
+* **Function Calls**: Keeping track of function calls in recursion.
+
+Stacks are simple but powerful, forming the backbone of many computer science algorithms and operations.
+
+### Resources
+
+* [AlgoMonster](https://algo.monster/problems/stack_intro)
+* [Programiz](https://www.programiz.com/dsa/stack)

content/2.dsa/2.data-structures-i/_dir.yml

@@ -0,0 +1,4 @@
+title: Data Structures (I)
+navigation.redirect: /dsa/data-structures-i/stack
+
+

nuxt.config.ts

@@ -1,6 +1,11 @@
 // https://nuxt.com/docs/api/configuration/nuxt-config
 export default defineNuxtConfig({
-  devtools: { enabled: true },
-  extends: ['shadcn-docs-nuxt'],
-  compatibilityDate: '2024-07-06',
-});
+    devtools: {enabled: true},
+    extends: ['shadcn-docs-nuxt'],
+    compatibilityDate: '2024-07-06',
+    mdc: {
+        highlight: {
+            langs: ['python']
+        }
+    }
+});