高精度压位加乘

#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
struct node
{
	int len;
	int num[30000];
	node(){len=0;memset(num,0,sizeof(num));}
	void xchili(char *in)
	{	
		int llen=strlen(in)-1;
		int x=0;
		len=(llen+1)/4-1;
		if((llen+1)%4)
			len++;
		int place=0;
		int time=1;
		for(int i=llen;i>=0;i--)
		{
			x=x+(in[i]-'0')*time;
			time*=10;
			if(time==10000)
			{
				num[place++]=x;
				x=0;
				time=1;
			}
		}
		if((llen+1)%4)
			num[len]=x;
	}
	node operator *(node &b)
	{
		node k;
		for(int i=0;i<=len;i++)
			for(int j=0;j<=b.len;j++)
			{
				k.num[i+j]+=num[i]*b.num[j];
				k.num[i+j+1]+=k.num[i+j]/10000;
				k.num[i+j]%=10000;
			}
		k.len=len+b.len+1;
		while(k.num[k.len]==0&&k.len)
			k.len--;
		return k; 
	}
	node operator +(node &b)
	{
		node re;
		int llen=max(len,b.len);
		for(int i=0;i<=llen;i++)
		{
			re.num[i]=num[i]+b.num[i];
			re.num[i+1]+=re.num[i]/10000;
			re.num[i]%=10000;
		}
		re.len=llen;
		if(re.num[re.len+1])
			re.len++;
		return re;
	}
};
char a[3000],b[3000];
node work(char *in)
{
}
node ans1,ans2,out;
int main() 
{
	//cin>>a>>b;
	/*scanf("%s",a);
	scanf("%s",b);*/
	int n;
	scanf("%d",&n);
	int mode=2;
	//scnaf("%d",&mode);
	if(mode==1)
	{		
		if(a[0]=='-'&&b[0]!='-')
		{
			cout<<"-";
			//ans1=work(a+1);
			ans1.xchili(a+1);
			//ans2=work(b);
			ans2.xchili(b);
		}
		if(a[0]!='-'&&b[0]=='-')
		{
			cout<<"-";
			//ans1=work(a);
			ans1.xchili(a);
			//ans2=work(b+1);
			ans2.xchili(b+1);
		}
		if(a[0]=='-'&&b[0]=='-')
		{
			//ans1=work(a+1);
			ans1.xchili(a+1);
			//ans2=work(b+1);
			ans1.xchili(b+1);
		}
		if(a[0]!='-'&&b[0]!='-')
		{
			//ans1=work(a);
			ans1.xchili(a);
			//ans2=work(b);
			ans2.xchili(b);
		}
		out=ans1*ans2;
		printf("%d",out.num[out.len]);
		for(int i=out.len-1;i>=0;i--)
		{
			/*if(out.num[i]==0&&i!=out.len)
			{
				cout<<"0000";
				continue;
			}
			if(out.num[i]<10&&i!=out.len)
			{
				cout<<"000"<<out.num[i];
				continue;
			}
			if(out.num[i]<100&&i!=out.len)
			{
				cout<<"00"<<out.num[i];
				continue;
			}
			if(out.num[i]<1000&&i!=out.len)
			{
				cout<<"0"<<out.num[i];
				continue;
			}
			cout<<out.num[i];*/
			printf("%04d",out.num[i]); 
		}
	 } 
	if(mode==2)
	{
		node e,f,c;
		e.len=0;e.num[0]=1;
		f.len=0;f.num[0]=2;
		if(n>=3)
		{
			for(int i=3;i<=n;i++)
			{
				c=e+f;
				e=f;
				f=c;
			}
			printf("%d",c.num[c.len]);
			for(int i=c.len-1;i>=0;i--)
				printf("%04d",c.num[i]);
		}
		if(n==2)
			printf("2");
		if(n==1)
			printf("1");
		if(n==0)
			printf("1");
	}
	return 0;
}