Metric Converter Library - Problem

Create a comprehensive metric conversion library that provides functions to convert between commonly used units. Your library should handle conversions between the following unit pairs:

Distance: kilometers ↔ miles
Weight: kilograms ↔ pounds
Temperature: Celsius ↔ Fahrenheit
Volume: liters ↔ gallons (US)

Implement a function that takes a value, from_unit, and to_unit as parameters and returns the converted value. The function should handle all conversions accurately using the standard conversion formulas.

Conversion Formulas:

1 kilometer = 0.621371 miles
1 kilogram = 2.20462 pounds
°F = (°C × 9/5) + 32
1 liter = 0.264172 gallons

Input & Output

Example 1 — Distance Conversion

$ Input: value = 100, from_unit = "km", to_unit = "miles"

› Output: 62.1371

💡 Note: Converting 100 kilometers to miles: 100 × 0.621371 = 62.1371 miles

Example 2 — Temperature Conversion

$ Input: value = 0, from_unit = "celsius", to_unit = "fahrenheit"

› Output: 32.0

💡 Note: Converting 0°C to Fahrenheit: (0 × 9/5) + 32 = 32°F (freezing point of water)

Example 3 — Weight Conversion

$ Input: value = 70, from_unit = "kg", to_unit = "lbs"

› Output: 154.3234

💡 Note: Converting 70 kilograms to pounds: 70 × 2.20462 = 154.3234 lbs

Constraints

value is a positive number
from_unit and to_unit are valid unit strings
Supported units: km, miles, kg, lbs, celsius, fahrenheit, liters, gallons

Visualization

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Asked in

G Google 15 a Amazon 12 M Microsoft 10

Build a unified conversion function that handles multiple unit types (distance, weight, temperature, volume). The optimal approach uses conversion factor maps for efficient lookup instead of lengthy if-else chains. Time: O(1), Space: O(1)

Common Approaches

✓ Map-Based Conversion Table

⏱️ Time: O(1) Space: O(1)

Create conversion tables using maps/dictionaries that store conversion factors and special handling for temperature. Look up the conversion factor based on unit pairs and apply the appropriate mathematical operation.

Separate Function for Each Conversion

⏱️ Time: O(1) Space: O(1)

Write separate functions for each possible conversion (km_to_miles, miles_to_km, kg_to_lbs, etc.). Use if-else chains to determine which function to call based on the from_unit and to_unit parameters.

Map-Based Conversion Table — Algorithm Steps

Create conversion factor maps for each unit type
Look up conversion factor based on from/to units
Apply conversion formula or simple multiplication

Visualization

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Step-by-Step Walkthrough

Input

Receive conversion parameters

Lookup

Find conversion factor in map

Calculate

Apply factor to get result

Code -

solution.c — C

#include <stdio.h>
#include <string.h>

double solution(double value, char* fromUnit, char* toUnit) {
    // Handle temperature conversions
    if (strcmp(fromUnit, "celsius") == 0 && strcmp(toUnit, "fahrenheit") == 0) {
        return (value * 9.0/5.0) + 32;
    }
    if (strcmp(fromUnit, "fahrenheit") == 0 && strcmp(toUnit, "celsius") == 0) {
        return (value - 32) * 5.0/9.0;
    }
    
    // Handle same unit
    if (strcmp(fromUnit, toUnit) == 0) {
        return value;
    }
    
    // Handle distance conversions
    if (strcmp(fromUnit, "km") == 0 && strcmp(toUnit, "miles") == 0) {
        return value * 0.621371;
    }
    if (strcmp(fromUnit, "miles") == 0 && strcmp(toUnit, "km") == 0) {
        return value * 1.609344;
    }
    
    // Handle weight conversions
    if (strcmp(fromUnit, "kg") == 0 && strcmp(toUnit, "lbs") == 0) {
        return value * 2.20462;
    }
    if (strcmp(fromUnit, "lbs") == 0 && strcmp(toUnit, "kg") == 0) {
        return value * 0.453592;
    }
    
    // Handle volume conversions
    if (strcmp(fromUnit, "liters") == 0 && strcmp(toUnit, "gallons") == 0) {
        return value * 0.264172;
    }
    if (strcmp(fromUnit, "gallons") == 0 && strcmp(toUnit, "liters") == 0) {
        return value * 3.78541;
    }
    
    return value;
}

int main() {
    double value;
    char fromUnit[50], toUnit[50];
    scanf("%lf", &value);
    scanf("%s", fromUnit);
    scanf("%s", toUnit);
    printf("%f\n", solution(value, fromUnit, toUnit));
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(1)

HashMap lookup is O(1) plus single arithmetic operation

✓ Linear Growth

Space Complexity

O(1)

Fixed-size conversion tables regardless of input

✓ Linear Space

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Medium Frequency

~15 min Avg. Time

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Metric Converter Library - Problem

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Map-Based Conversion Table — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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