// C implementation with multiple passes
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

typedef struct {
    char category[50];
    int sales[7];
} CategorySales;

CategorySales* salesByDayBruteForce(Order* orders, int orderCount, Item* items, int itemCount, int* resultSize) {
    // Create item to category mapping
    char itemToCategory[1000][50]; // Assume max 1000 items
    
    // Initialize mapping
    for (int i = 0; i < itemCount; i++) {
        strcpy(itemToCategory[i], items[i].itemCategory);
    }
    
    CategorySales* result = malloc(100 * sizeof(CategorySales));
    int categoryCount = 0;
    
    // Inefficient: scan orders 7 times, once for each day
    for (int dayIdx = 0; dayIdx < 7; dayIdx++) {
        for (int i = 0; i < orderCount; i++) {
            struct tm orderTm;
            strptime(orders[i].orderDate, "%Y-%m-%d", &orderTm);
            int dayOfWeek = (orderTm.tm_wday + 6) % 7; // Convert to Mon=0
            
            if (dayOfWeek == dayIdx) {
                // Find category for this item
                char* category = NULL;
                for (int j = 0; j < itemCount; j++) {
                    if (strcmp(items[j].itemId, orders[i].itemId) == 0) {
                        category = items[j].itemCategory;
                        break;
                    }
                }
                
                if (category) {
                    // Find or create category entry
                    int categoryIdx = -1;
                    for (int k = 0; k < categoryCount; k++) {
                        if (strcmp(result[k].category, category) == 0) {
                            categoryIdx = k;
                            break;
                        }
                    }
                    
                    if (categoryIdx == -1) {
                        strcpy(result[categoryCount].category, category);
                        memset(result[categoryCount].sales, 0, 7 * sizeof(int));
                        categoryIdx = categoryCount++;
                    }
                    
                    result[categoryIdx].sales[dayIdx] += orders[i].quantity;
                }
            }
        }
    }
    
    *resultSize = categoryCount;
    return result;
}