Coding Problems

Find Nth Fibonacci Number

Find Nth Fibonacci Number

Bruce Ediger

Daily Coding Problem: Problem #1790 [Easy]

Implement the function fib(n), which returns the nth number in the Fibonacci sequence, using only O(1) space.

Divided Palindromes Daily Coding Problem

Divided Palindromes Daily Coding Problem

Bruce Ediger

Problem Statement

Given a list of words, find all pairs of unique indices such that the concatenation of the two words is a palindrome.

For example, given the list [“code”, “edoc”, “da”, “d”], return [(0, 1), (1, 0), (2, 3)].

Mergesort Investigation 10 - garbage collection

Mergesort Investigation 10 - garbage collection

Bruce Ediger

Previously, in July 2021, I had tried to remove garbage collection from the possible variables affecting my iterative mergesort. I transliterated the Go code to a plain C version that could not have any garbage collection. The C code benchmarked very similarly to the Go code.

Daily Coding Problem: Problem #1780 [Medium]

Daily Coding Problem: Problem #1780 [Medium]

Bruce Ediger

Problem statement

This problem was asked by Cisco.

Given an unsigned 8-bit integer, swap its even and odd bits. The 1st and 2nd bit should be swapped, the 3rd and 4th bit should be swapped, and so on.

For example, 10101010 should be 01010101. 11100010 should be 11010001.

Bonus: Can you do this in one line?

Mergesort Investigation 8 - bottom up

Mergesort Investigation 8 - bottom up

Bruce Ediger

I thought that since the purely recursive implementation of mergesort didn’t show weird, abrupt performance drops, traversing linked lists (no matter what order the nodes appeared in memory) also did not show abrupt performance drops, and that node size in memory caused different performance oddities, that the iterative implementation’s memory access patterns might be the cause.