Plant the Crop - Free Code Camp #155 Daily Challenge

2026-01-12 2 min

Table of Contents

Plant The Crop - Analysis and Explanation

Problem Statement

Given:

A number representing the size of a field
A unit of measurement (‘acres’ or ‘hectares’)
A crop type

Determine how many plants of that crop fit in the field.

Unit conversion:

1 acre = 4046.86 m²
1 hectare = 10,000 m²

Space required per plant:

Crop	m² per plant
corn	1
wheat	0.1
soybeans	0.5
tomatoes	0.25
lettuce	0.2

Return the number of plants that fit, rounded down.

Initial Analysis

What does the challenge ask?

Convert the field area to square meters, look up the space required per plant for the crop, and divide. The result is rounded down.

Test Cases

getNumberOfPlants(1, 'acres', 'corn') // 4046
getNumberOfPlants(2, 'hectares', 'lettuce') // 100000
getNumberOfPlants(20, 'acres', 'soybeans') // 161874
getNumberOfPlants(3.75, 'hectares', 'tomatoes') // 150000
getNumberOfPlants(16.75, 'acres', 'tomatoes') // 271139

Solution Development

Approach and Diagram

Convert the area to m² according to the unit.
Look up the space per plant for the crop.
Divide total area by space per plant.
Round down.

flowchart TD
  A["Input: size, unit, crop"] --> B["Convert to m²"]
  B --> C["Look up space per plant"]
  C --> D["Divide area / space"]
  D --> E["Round down"]
  E --> F["Result: plants"]

JavaScript Implementation

function getNumberOfPlants(size, unit, crop) {
  const unitToM2 = {
    acres: 4046.86,
    hectares: 10000,
    hectáreas: 10000, // just in case
  }
  const cropToM2 = {
    corn: 1,
    wheat: 0.1,
    soybeans: 0.5,
    tomatoes: 0.25,
    lettuce: 0.2,
  }
  const area = size * unitToM2[unit]
  const space = cropToM2[crop]
  return Math.floor(area / space)
}

Complexity Analysis

Time: $O(1)$ (dictionary access and basic arithmetic)
Space: $O(1)$ (scalar variables and small dictionaries)

Edge Cases and Considerations

If the unit or crop does not exist, returns NaN or undefined (assume valid input).
If the size is 0, returns 0.
If the size is negative, returns negative or NaN (not handled).
If the space per plant is greater than the area, returns 0.

Reflections and Learnings

Dictionaries to map units and crops.
Unit conversion and basic arithmetic.
Rounding down to avoid exceeding real capacity.

What could be improved?

Validate unrecognized or negative inputs.
Internationalize units if needed.

Resources and References

daily-challenge freecodecamp