输入输出外挂（整数）

void out(int a)  
{  
    if(a < 0) {putchar('-'); a = -a;}  
    if(a >= 10)out(a / 10);  
    putchar(a % 10 + '0');  
}  
int in()  
{  
    int flag = 1;  
    char ch;  
    int a = 0;  
    while((ch = getchar()) == ' ' || ch == '\n');  
    if(ch == '-') flag = -1;  
    else  
    a += ch - '0';  
    while((ch = getchar()) != ' ' && ch != '\n')  
    {  
        a *= 10;  
        a += ch - '0';  
    }  
    return flag * a;  
}