library(tidyverse)
library(readxl)
path <- "Excel/800-899/853/853 Collatz Sequence.xlsx"
input <- read_excel(path, range = "A2:A9")
test <- read_excel(path, range = "B2:B9")
csteps <- function(n) { s <- 0; while(n > 1) { n <- if(n %% 2) 3*n + 1 else n/2; s <- s + 1 }; s }
result <- input %>% mutate(Steps = map_dbl(`Start Number`, csteps))
all.equal(result$Steps, test$Steps)
# [1] TRUEExcel BI - Excel Challenge 853
excel-challenges
excel-formulas
🔰 For the given numbers, find the number of steps needed to reach 1.
Challenge Description
🔰 For the given numbers, find the number of steps needed to reach 1. (Colum C - Collatz Decomposition has been given to back the answer)
Solutions
- Logic: Read the workbook ranges needed for the challenge; Derive the required intermediate columns.
- Strengths: The code maps the workbook rule into a compact, reproducible pipeline.
- Areas for Improvement: The solution assumes the workbook layout and selected ranges remain stable, so any structural change in the sheet would require small adjustments.
- Gem: The elegant part is how little code is needed once the correct intermediate representation is chosen.
import pandas as pd
path = "Excel/800-899/853/853 Collatz Sequence.xlsx"
input = pd.read_excel(path, usecols="A", skiprows=1, nrows=8)
test = pd.read_excel(path, usecols="B", skiprows=1, nrows=8)
collatz_steps = lambda n: 0 if n == 1 else 1 + collatz_steps(3 * n + 1 if n % 2 else n // 2)
input["Steps"] = input.iloc[:, 0].apply(collatz_steps)
print(input["Steps"].equals(test["Steps"]))
# TrueThe Python version mirrors the same workbook logic with a concise, direct implementation.
Difficulty Level
Easy / Medium
The business rule is clear, though the workbook still needs a few transformation steps to reach the expected output.