Omid - Challenge 2

data-challenges
advanced-exercises
🔰 Group Group the rows from top which in each group the total cost be lower than 130$.
Published

March 24, 2026

Illustration for Omid - Challenge 2

Challenge Description

🔰 Group Group the rows from top which in each group the total cost be lower than 130$.

Solutions

library(tidyverse)
library(readxl)
library(MESS)

path = "files/CH-002.xlsx"
input = read_excel(path, range = "B2:C19")
test  = read_excel(path, range = "H2:J19")

result = input %>%
  mutate(Group = cumsumbinning(Cost, 120))

all.equal(result$Group, test$Group, check.attributes = FALSE)
#> [1] TRUE

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • Builds the intermediate columns that drive the final result

  • Strengths:

    • The R solution stays close to the workbook rule and keeps the transformation compact.

  • Areas for Improvement:

    • The code assumes the sheet structure and source ranges remain stable.

  • Gem:

    • The strongest part of the solution is choosing the right intermediate representation before shaping the final output.
import pandas as pd

path = "CH-002.xlsx"
input_data = pd.read_excel(path, usecols="B:C", skiprows=1, nrows=18)
test = pd.read_excel(path, usecols="H:J", skiprows=1, nrows=18)

def cumsumbinning(values, limit):
    groups = []
    current_group = 1
    running = 0
    for value in values:
        if running + value > limit and running > 0:
            current_group += 1
            running = 0
        running += value
        groups.append(current_group)
    return groups

result = input_data.copy()
result["Group"] = cumsumbinning(result["Cost"], 120)

print(result["Group"].equals(test["Group"]))

  • Logic:

    • Reads the workbook ranges needed for the challenge

    • Applies the rule iteratively until the output stabilizes

  • Strengths:

    • The Python version follows the same rule in a direct dataframe-oriented implementation.

  • Areas for Improvement:

    • The code assumes the workbook layout remains stable, so any sheet redesign would require small adjustments.

  • Gem:

    • The implementation stays close to the original workbook rule instead of adding unnecessary abstraction.

Difficulty Level

This task is moderate:

  • The business rule is readable, but the workbook still requires careful implementation to reach the expected layout.