快速输入

void scani(int &num){
    char ch;
    int flag=1;
    while(ch=getchar(),(ch>'9'||ch<'0')&&(ch!='-'));
    if(ch=='-')
        flag=-1,num=0;
    else
        num=ch-'0';
    while(ch=getchar(),ch<='9'&&ch>='0')
        num=num*10+ch-'0';
    num*=flag;
}