Python Patterns & Logic Building

Master Python through visual patterns and logical thinking. Click on any question to reveal the solution with smooth animation.

Each solution includes detailed explanation

Star Pattern Challenges

Pattern 1: Increasing Triangle

Easy

Print stars in increasing order per row.

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Solution

For Loop

for i in range(1, 5):
    print("*" * i)

Explanation: The outer loop runs 4 times (i = 1 to 4). In each iteration, we print '*' multiplied by i, which creates the increasing triangle pattern.

Pattern 2: Reverse Triangle

Easy

Print stars in decreasing order per row.

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*

Solution

Reverse Range

for i in range(4, 0, -1):
    print("*" * i)

Explanation: Using range(4, 0, -1) gives us values 4, 3, 2, 1. We print '*' multiplied by i in each iteration, creating the decreasing pattern.

Pattern 3: Right Aligned Triangle

Medium

Align stars to the right with spaces.

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Solution

String Concatenation

for i in range(1, 5):
    print(" " * (4 - i) + "*" * i)

Explanation: We print spaces before the stars to align them to the right. The number of spaces decreases as the number of stars increases.

Pattern 4: Pyramid

Medium

Create a symmetrical pyramid pattern.

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  ***
 *****
*******

Solution

Mathematical Pattern

for i in range(1, 5):
    print(" " * (4 - i) + "*" * (2*i - 1))

Explanation: The pattern uses the formula (2*i - 1) to determine the number of stars in each row. This creates an odd number sequence: 1, 3, 5, 7 stars.

Logic Building Questions

Q1. Check Prime Number

Fundamental

Write a program to check whether a number is prime. A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Input Example: 7
Output: "Prime"

Prime Number Solution

Conditionals & Loops

num = int(input("Enter a number: "))

if num > 1:
    for i in range(2, num):
        if num % i == 0:
            print(f"{num} is not a prime number")
            break
    else:
        print(f"{num} is a prime number")
else:
    print(f"{num} is not a prime number")

Explanation: We check if the number is greater than 1, then test divisibility from 2 up to num-1. If any divisor is found, the number is not prime.

Time Complexity: O(n)
Optimization Tip: We only need to check up to √n

Q2. Factorial using Loop

Fundamental

Calculate factorial of a number using a loop. The factorial of a non-negative integer n is the product of all positive integers less than or equal to n.

Input Example: 5
Output: 120 (5! = 5×4×3×2×1 = 120)

Factorial Solution

For Loop

n = int(input("Enter a number: "))
factorial = 1

for i in range(1, n + 1):
    factorial *= i

print(f"The factorial of {n} is {factorial}")

Explanation: We initialize factorial as 1, then multiply it by each integer from 1 to n. The range(1, n+1) gives us 1, 2, 3, ..., n.

Time Complexity: O(n)
Note: Factorial grows rapidly; 20! is the largest that fits in 64-bit

Q3. Fibonacci Series

Intermediate

Generate the Fibonacci series up to n terms. Each number is the sum of the two preceding ones, starting from 0 and 1.

Input Example: 8
Output: 0, 1, 1, 2, 3, 5, 8, 13

Fibonacci Solution

Sequence Generation

n = int(input("Enter number of terms: "))

# First two terms
a, b = 0, 1
count = 0

if n <= 0:
    print("Please enter a positive integer")
elif n == 1:
    print(f"Fibonacci sequence up to {n}:")
    print(a)
else:
    print(f"Fibonacci sequence up to {n}:")
    while count < n:
        print(a, end=", ")
        c = a + b
        a = b
        b = c
        count += 1

Explanation: We start with 0 and 1, then generate the next term by adding the previous two. The variables a and b are updated in each iteration to move through the sequence.