奶牛和公牛

　

char * getHint(char * secret, char * guess){
    if (secret == NULL || guess == NULL) {
        return "0A0B";
    }
    int len, i, bulls=0, cows=0;
    int nums1[10]={0}, nums2[10]={0};
    char *res;
    res = calloc(sizeof(char) * 1000, 1);

    len = strlen(secret);
    for (i=0; i<len; ++i) {
        if (secret[i] == guess[i]) {++bulls;}
        else {
            nums1[secret[i]]++;
            nums2[guess[i]]++;
        }
    }

    for (i=0; i<10; ++i) {
        cows += ((nums1[i] < nums2[i]) ? nums1[i]:nums2[i]);
    }
    sprintf(res, "%dA%dB", bulls, cows);
    return res;
}