题目：
题解：
cpp
typedef struct {
char key[32];
int val;
UT_hash_handle hh;
} HashItem;
int* findSubstring(char * s, char ** words, int wordsSize, int* returnSize){
int m = wordsSize, n = strlen(words[0]), ls = strlen(s);
int *res = (int *)malloc(sizeof(int) * ls);
int pos = 0;
for (int i = 0; i < n; i++) {
if (i + m * n > ls) {
break;
}
HashItem *diff = NULL;
char word[32] = {0};
for (int j = 0; j < m; j++) {
snprintf(word, n + 1, "%s", s + i + j * n);
HashItem * pEntry = NULL;
HASH_FIND_STR(diff, word, pEntry);
if (NULL == pEntry) {
pEntry = (HashItem *)malloc(sizeof(HashItem));
strcpy(pEntry->key, word);
pEntry->val = 0;
HASH_ADD_STR(diff, key, pEntry);
}
pEntry->val++;
}
for (int j = 0; j < m; j++) {
HashItem * pEntry = NULL;
HASH_FIND_STR(diff, words[j], pEntry);
if (NULL == pEntry) {
pEntry = (HashItem *)malloc(sizeof(HashItem));
strcpy(pEntry->key, words[j]);
pEntry->val = 0;
HASH_ADD_STR(diff, key, pEntry);
}
pEntry->val--;
if (pEntry->val == 0) {
HASH_DEL(diff, pEntry);
free(pEntry);
}
}
for (int start = i; start < ls - m * n + 1; start += n) {
if (start != i) {
char word[32];
snprintf(word, n + 1, "%s", s + start + (m - 1) * n);
HashItem * pEntry = NULL;
HASH_FIND_STR(diff, word, pEntry);
if (NULL == pEntry) {
pEntry = (HashItem *)malloc(sizeof(HashItem));
strcpy(pEntry->key, word);
pEntry->val = 0;
HASH_ADD_STR(diff, key, pEntry);
}
pEntry->val++;
if (pEntry->val == 0) {
HASH_DEL(diff, pEntry);
free(pEntry);
}
snprintf(word, n + 1, "%s", s + start - n);
pEntry = NULL;
HASH_FIND_STR(diff, word, pEntry);
if (NULL == pEntry) {
pEntry = (HashItem *)malloc(sizeof(HashItem));
strcpy(pEntry->key, word);
pEntry->val = 0;
HASH_ADD_STR(diff, key, pEntry);
}
pEntry->val--;
if (pEntry->val == 0) {
HASH_DEL(diff, pEntry);
free(pEntry);
}
}
if (HASH_COUNT(diff) == 0) {
res[pos++] = start;
}
}
HashItem *curr, *tmp;
HASH_ITER(hh, diff, curr, tmp) {
HASH_DEL(diff, curr);
free(curr);
}
}
*returnSize = pos;
return res;
}