1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#define MAX_LENGTH 100
5
6// Define a struct for map entries
7typedef struct {
8    char domain[MAX_LENGTH];
9    int count;
10} DomainCountEntry;
11
12// Custom hashmap-like array
13typedef struct {
14    DomainCountEntry *entries;
15    int size;
16    int capacity;
17} DomainCountMap;
18
19void initMap(DomainCountMap *map, int capacity) {
20    map->entries = (DomainCountEntry *)malloc(capacity * sizeof(DomainCountEntry));
21    map->size = 0;
22    map->capacity = capacity;
23}
24
25void freeMap(DomainCountMap *map) {
26    free(map->entries);
27}
28
29int findIndex(DomainCountMap *map, const char *domain) {
30    for (int i = 0; i < map->size; i++) {
31        if (strcmp(map->entries[i].domain, domain) == 0) {
32            return i;
33        }
34    }
35    return -1;
36}
37
38void insertOrUpdate(DomainCountMap *map, const char *domain, int count) {
39    int index = findIndex(map, domain);
40    if (index == -1) {
41        // New entry
42        strcpy(map->entries[map->size].domain, domain);
43        map->entries[map->size].count = count;
44        map->size++;
45        if (map->size == map->capacity) {
46            // Increase capacity
47            map->capacity *= 2;
48            map->entries = (DomainCountEntry *)realloc(map->entries, map->capacity * sizeof(DomainCountEntry));
49        }
50    } else {
51        // Update existing count
52        map->entries[index].count += count;
53    }
54}
55
56void processDomains(const char **domains, int size, char ***result, int *resultSize) {
57    DomainCountMap map;
58    initMap(&map, 10);
59
60    for (int i = 0; i < size; i++) {
61        const char *cpdomain = domains[i];
62        int count;
63        char domain[MAX_LENGTH];
64        sscanf(cpdomain, "%d %s", &count, domain);
65
66        // Process domain
67        char *token = strtok(domain, ".");
68        char subdomain[MAX_LENGTH] = "";
69        char buffer[MAX_LENGTH];
70
71        while (token) {
72            if (*subdomain) {
73                snprintf(buffer, sizeof(buffer), "%s.%s", token, subdomain);
74            } else {
75                snprintf(buffer, sizeof(buffer), "%s", token);
76            }
77            strcpy(subdomain, buffer);
78            insertOrUpdate(&map, subdomain, count);
79
80            token = strtok(NULL, ".");
81        }
82    }
83
84    // Prepare result
85    *result = (char **)malloc(map.size * sizeof(char *));
86    *resultSize = map.size;
87    for (int i = 0; i < map.size; i++) {
88        (*result)[i] = (char *)malloc(MAX_LENGTH);
89        snprintf((*result)[i], MAX_LENGTH, "%d %s", map.entries[i].count, map.entries[i].domain);
90    }
91
92    freeMap(&map);
93}
94
95int main() {
96    const char *cpdomains[] = {"9001 discuss.leetcode.com", "900 google.mail.com", "50 yahoo.com", "1 intel.mail.com", "5 wiki.org"};
97    char **result;
98    int resultSize;
99
100    processDomains(cpdomains, 5, &result, &resultSize);
101
102    // Print results
103    for (int i = 0; i < resultSize; i++) {
104        printf("%s\n", result[i]);
105        free(result[i]);  // Free each result
106    }
107    free(result);  // Free result array
108
109    return 0;
110}

1Implementing a Trie in C is non