2781. 最长合法子字符串的长度

C代码：滑动窗口、哈希表

typedef struct{
    char* str;
    UT_hash_handle hh;
} HashTable;

HashTable* head;

void AddToHash(char* str) {
    HashTable* out = (HashTable*)malloc(sizeof(HashTable));
    out->str = str;
    HASH_ADD_STR(head, str, out);
}

bool FindStr(char* word, int r, int j) {
    HashTable* out = NULL;
    char* str = (char*)malloc(sizeof(char) * 11);
    str[0] = '\0';
    strncat(str, word + j, r - j + 1);
    HASH_FIND_STR(head, str, out);
    return out != NULL;
}

int longestValidSubstring(char * word, char ** forbidden, int forbiddenSize){
    head = NULL;
    for (int i = 0; i < forbiddenSize; ++i) {
        AddToHash(forbidden[i]);
    }
    int len = strlen(word);
    int l = 0;
    int ans = 0;
    for (int r = 0; r < len; ++r) {
        for (int j = r; j >= fmax(l, r - 10 + 1); --j) {
            if (FindStr(word, r, j)) {
                l = j + 1;
                break;
            }
        }
        if (r >= l) {
            ans = fmax(ans, r - l + 1);
        }
    }
    return ans;
}