题目：

题解：

struct hashTable {
    int key;
    int val;
    UT_hash_handle hh;
};

int firstUniqChar(char* s) {
    struct hashTable* position = NULL;
    int que[26][2], left = 0, right = 0;
    int n = strlen(s);
    for (int i = 0; i < n; ++i) {
        int ikey = s[i];
        struct hashTable* tmp;
        HASH_FIND_INT(position, &ikey, tmp);
        if (tmp == NULL) {
            tmp = malloc(sizeof(struct hashTable));
            tmp->key = ikey;
            tmp->val = i;
            HASH_ADD_INT(position, key, tmp);
            que[right][0] = ikey;
            que[right++][1] = i;
        } else {
            tmp->val = -1;
            while (left < right) {
                int ikey = que[left][0];
                struct hashTable* tmp;
                HASH_FIND_INT(position, &ikey, tmp);
                if (tmp == NULL || tmp->val != -1) {
                    break;
                }
                left++;
            }
        }
    }
    return left < right ? que[left][1] : -1;
}