Weekly Challenge

Five puzzles.
One coffee.

Five geeky, techie puzzles. Solve all five, submit your answers, and one correct entry wins a coffee — on me. Puzzles update once a winner has been found.

☕ One winner · One coffee · Per puzzle set
Your progress 0 / 5 solved
01 — Easy Binary
✓ Solved

What does the machine say?

Decode the following binary. Each 8-bit group is one ASCII character. What word does it spell?

01001100 01000101 01000001 01000100 01000101 01010010
Each group of 8 digits is a binary number. Convert each to decimal, then look up the ASCII table.
02 — Easy Code Output
✓ Solved

What does this print?

Without running it — what number does this Python code output?

result = sum([x**2 for x in range(1, 6)]) print(result)
range(1, 6) gives you 1, 2, 3, 4, 5. Square each one. Then add them up.
03 — Medium Logic
✓ Solved

The infinite loop

I call myself. I have no end unless you give me one. I live inside functions and can consume the whole stack. Mathematicians love me. Beginners fear me. What am I?

To understand me, you must first understand me.
04 — Medium Hexadecimal
✓ Solved

Hex to decimal

Convert the following hexadecimal number to decimal. This is the answer you're looking for:

0xFF
In hex, F = 15. The first digit is multiplied by 16, the second by 1.
05 — Hard Algorithm
✓ Solved

The missing number

You are given an array containing every integer from 1 to 100 — except one. The array has been shuffled. You may only pass through it once. No sorting allowed. What is the most elegant way to find the missing number, and what is the missing number in this sequence?

// Sum of 1→100 is known. Array sum is given as: array_sum = 4949

What number is missing? (Bonus: name the technique)

The sum of integers 1 to n = n(n+1)/2. You know what the full sum should be. You know what it is. The difference is your answer.

Got all five?
Claim your coffee.

Submit your answers below. One correct entry is picked at random and wins a coffee voucher — sent directly to you. New puzzles drop once a winner has been found.