Custom Sort Comparator - Problem

You are given an array of product objects. Each product has three properties: category (string), price (integer), and name (string).

Sort the products using a custom comparator with multiple criteria:

First by category (alphabetically ascending)
Then by price (numerically ascending)
Finally by name (alphabetically ascending)

Return the sorted array of products.

Input & Output

Example 1 — Mixed Categories and Prices

$ Input: products = [{"category":"Electronics","price":50,"name":"Tablet"},{"category":"Books","price":15,"name":"Novel"},{"category":"Books","price":25,"name":"Guide"},{"category":"Electronics","price":30,"name":"Mouse"}]

› Output: [{"category":"Books","price":15,"name":"Novel"},{"category":"Books","price":25,"name":"Guide"},{"category":"Electronics","price":30,"name":"Mouse"},{"category":"Electronics","price":50,"name":"Tablet"}]

💡 Note: First sort by category: Books comes before Electronics. Within Books category, $15 Novel comes before $25 Guide by price. Within Electronics, $30 Mouse comes before $50 Tablet.

Example 2 — Same Category, Same Price

$ Input: products = [{"category":"Books","price":20,"name":"Zebra"},{"category":"Books","price":20,"name":"Apple"}]

› Output: [{"category":"Books","price":20,"name":"Apple"},{"category":"Books","price":20,"name":"Zebra"}]

💡 Note: Same category and price, so sort by name alphabetically: Apple comes before Zebra.

Example 3 — Single Product

$ Input: products = [{"category":"Games","price":60,"name":"Chess"}]

› Output: [{"category":"Games","price":60,"name":"Chess"}]

💡 Note: Only one product, so the result is the same as input.

Constraints

1 ≤ products.length ≤ 1000
1 ≤ category.length, name.length ≤ 100
1 ≤ price ≤ 10000
category and name contain only letters and spaces

Visualization

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Asked in

G Google 45 a Amazon 38 M Microsoft 32 Apple 28

The key insight is using a custom comparator that implements multi-level sorting criteria in priority order. Best approach uses built-in sort with custom comparator for O(n log n) efficiency instead of manual bubble sort. Time: O(n log n), Space: O(log n).

Common Approaches

✓ Bubble Sort with Custom Comparator

⏱️ Time: O(n²) Space: O(1)

Implement bubble sort manually, comparing each pair of products using our custom logic. For each comparison, check category first, then price, then name in order of priority.

Built-in Sort with Custom Comparator

⏱️ Time: O(n log n) Space: O(log n)

Leverage the efficient built-in sorting algorithm (typically QuickSort or MergeSort) and provide a custom comparator function that handles our multi-criteria sorting requirements.

Bubble Sort with Custom Comparator — Algorithm Steps

Compare adjacent products using custom criteria
Swap if they are in wrong order
Repeat until no swaps needed

Visualization

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Step-by-Step Walkthrough

Compare Adjacent

Check if products[j] and products[j+1] need swapping

Apply Criteria

Use category → price → name priority

Repeat Passes

Continue until fully sorted

Code -

solution.c — C

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

typedef struct {
    char category[100];
    int price;
    char name[100];
} Product;

int compareProducts(Product a, Product b) {
    // Compare category first
    int catCmp = strcmp(a.category, b.category);
    if (catCmp != 0) return catCmp;
    
    // Same category, compare price
    if (a.price != b.price) return a.price - b.price;
    
    // Same price, compare name
    return strcmp(a.name, b.name);
}

Product* solution(Product* products, int n) {
    // Bubble sort with custom comparator
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (compareProducts(products[j], products[j + 1]) > 0) {
                Product temp = products[j];
                products[j] = products[j + 1];
                products[j + 1] = temp;
            }
        }
    }
    
    return products;
}

int main() {
    // Manual JSON parsing would be implemented here
    Product products[100];
    int n = 0;
    
    Product* result = solution(products, n);
    
    // Output formatting
    printf("[");
    for (int i = 0; i < n; i++) {
        if (i > 0) printf(",");
        printf("{\"category\":\"%s\",\"price\":%d,\"name\":\"%s\"}", result[i].category, result[i].price, result[i].name);
    }
    printf("]\n");
    
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(n²)

Nested loops comparing each pair of products multiple times

⚡ Linearithmic

Space Complexity

O(1)

Only uses a few variables for swapping, sorts in-place

⚡ Linearithmic Space

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Medium Frequency

~15 min Avg. Time

890 Likes

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Smart Actions

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Custom Sort Comparator - Problem

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Bubble Sort with Custom Comparator — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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