#define MAX_INPUT_SIZE 10000#define MAX_RESULT_SIZE (MAX_INPUT_SIZE * 2 - 1)char a[MAX_INPUT_SIZE],b[MAX_INPUT_SIZE],res[MAX_RESULT_SIZE];void mult(char result[], char a[], char b[])//res一定要清空{    int al, bl;    // a length, b length    int ri, ai, bi;    // r index, a index, b index    char tmp, carry;    al = strlen(a);    bl = strlen(b);    carry = 0;    for (bi = bl-1; bi >= 0; bi--)    {        for (ai = al-1; ai >= 0; ai--)        {            ri = (bl-1-bi) + (al-1-ai);            tmp = (a[ai]-'0') * (b[bi]-'0') + result[ri] + carry;            result[ri] = tmp % 10;            carry = tmp / 10;        }        while (carry)        {            ri++;            tmp = result[ri] + carry;            result[ri] = tmp % 10;            carry = tmp / 10;        }    }    int i = MAX_RESULT_SIZE - 1;    while (!result[i]) i--;    while (i >= 0) result[i--] += '0';}void print(char result[]){    int i = MAX_RESULT_SIZE - 1;    while (!result[i]) i--;    while (i >= 0) putchar(result[i--] + '0');    putchar('\n');}