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🎮 Python Playground

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📝 Python Editor

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Try These

📋 Sample Programs

Click to load code into playground!

🧮

Calculator

Simple arithmetic calculator

🔢

Fibonacci Series

First N fibonacci numbers

⭐

Star Pattern

Triangle star pattern

📊

Multiplication Table

Table of any number

Challenge Yourself

🧩 Practice Problems

Level-wise problems — click to see solution!

🟢 Easy Problems

Q1. Swap two numbers without using a third variable.

Python
a, b = 10, 20
print(f"Before: a={a}, b={b}")
a, b = b, a
print(f"After: a={a}, b={b}")

Q2. Check if a number is even or odd.

Python
num = int(input("Number: "))
print(f"{num} is {'Even' if num%2==0 else 'Odd'}")

Q3. Find the largest of three numbers.

Python
a, b, c = 15, 42, 28
largest = max(a, b, c)
print(f"Largest: {largest}")

Q4. Sum of digits of a number (e.g., 123 → 1+2+3 = 6).

Python
num = int(input("Number: "))
digit_sum = sum(int(d) for d in str(num))
print(f"Sum of digits: {digit_sum}")

Q5. Reverse a string.

Python
text = input("Enter string: ")
print(f"Reversed: {text[::-1]}")

Q6. Count vowels in a string.

Python
text = input("String: ").lower()
vowels = sum(1 for c in text if c in "aeiou")
print(f"Vowels: {vowels}")

Q7. Print multiplication table of any number.

Python
n = int(input("Number: "))
for i in range(1, 11):
    print(f"{n} x {i} = {n*i}")

Q8. Simple interest calculator (SI = P*R*T/100).

Python
p = float(input("Principal: "))
r = float(input("Rate (%): "))
t = float(input("Time (years): "))
si = (p * r * t) / 100
print(f"Simple Interest: ₹{si:.2f}")

🟡 Medium Problems

Q1. Check if a number is prime.

Python
def is_prime(n):
    if n < 2: return False
    for i in range(2, int(n**0.5)+1):
        if n % i == 0: return False
    return True

num = int(input("Number: "))
print(f"{num} is {'Prime ✅' if is_prime(num) else 'Not Prime ❌'}")

Q2. Check if a string is palindrome.

Python
text = input("String: ").lower().replace(" ", "")
print(f"Palindrome: {'Yes ✅' if text == text[::-1] else 'No ❌'}")

Q3. Sort a list without using sort() function.

Python
# Bubble Sort
nums = [64, 34, 25, 12, 22, 11, 90]
n = len(nums)
for i in range(n):
    for j in range(0, n-i-1):
        if nums[j] > nums[j+1]:
            nums[j], nums[j+1] = nums[j+1], nums[j]
print(f"Sorted: {nums}")

Q4. Find the second largest number in a list.

Python
nums = [45, 12, 78, 34, 90, 23]
unique = list(set(nums))
unique.sort()
print(f"Second Largest: {unique[-2]}")

Q5. Count word frequency in a sentence.

Python
text = "apple banana apple cherry banana apple"
freq = {}
for word in text.split():
    freq[word] = freq.get(word, 0) + 1
for word, count in sorted(freq.items(), key=lambda x: -x[1]):
    print(f"{word}: {count}")

Q6. Matrix addition (2D list).

Python
A = [[1,2,3],[4,5,6],[7,8,9]]
B = [[9,8,7],[6,5,4],[3,2,1]]
result = [[A[i][j]+B[i][j] for j in range(3)] for i in range(3)]
for row in result:
    print(row)
# [10,10,10] [10,10,10] [10,10,10]

🔴 Hard Problems

Q1. Implement a Stack using a class.

Python
class Stack:
    def __init__(self):
        self.items = []
    def push(self, item):
        self.items.append(item)
    def pop(self):
        return self.items.pop() if self.items else "Stack Empty!"
    def peek(self):
        return self.items[-1] if self.items else None
    def size(self):
        return len(self.items)

s = Stack()
s.push(10); s.push(20); s.push(30)
print(s.pop())   # 30
print(s.peek())  # 20

Q2. Implement Binary Search algorithm.

Python
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

nums = [2, 5, 8, 12, 16, 23, 38, 56, 72, 91]
idx = binary_search(nums, 23)
print(f"Found at index: {idx}")  # 5

Q3. Create a Decorator to measure function execution time.

Python
import time
def timer(func):
    def wrapper(*args, **kwargs):
        start = time.time()
        result = func(*args, **kwargs)
        print(f"⏱️ {func.__name__}: {time.time()-start:.4f}s")
        return result
    return wrapper

@timer
def slow_sum(n):
    return sum(range(n))

slow_sum(10_000_000)

Q4. Implement Linked List.

Python
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None
    def append(self, data):
        new = Node(data)
        if not self.head:
            self.head = new; return
        curr = self.head
        while curr.next: curr = curr.next
        curr.next = new
    def display(self):
        curr = self.head
        while curr:
            print(curr.data, end=" → ")
            curr = curr.next
        print("None")

ll = LinkedList()
for x in [10,20,30,40]: ll.append(x)
ll.display()  # 10 → 20 → 30 → 40 → None