最无敌的3行+316行 题解100%AC

python:

a=int(input())
b=int(input())
print(a+b)

c++:

#include<cmath>
#include<iostream>
#include<cstring>
//********一些辅助函数与FFT实现
const double PI=4*atan(1);
template<typename T>
void Swap(T &a,T &b){
	T c=a;
	a=b;
	b=c;
	return;
}
template<typename T>
T Max(const T &a,const T &b){
	return a<b?b:a;
}
typedef long long ll;
struct comp{
	double real,imag;
	comp operator+(const comp &x)const{
		return {real+x.real,imag+x.imag};
	}
	comp operator-(const comp &x)const{
		return {real-x.real,imag-x.imag};
	}
	comp operator*(const comp &x)const{
		return {real*x.real-imag*x.imag,real*x.imag+x.real*imag};
	}
	comp operator/(const unsigned &x)const{
		return {real/(double)x,imag/(double)x};
	}
};
void FFT(comp *f,unsigned n,int rev){
	for(unsigned i=1,j=n>>1,k;i<n-1;i++){//位逆序置换
		if(i<j)
			Swap(f[i],f[j]);
		k=n>>1;
		while(j>=k){
			j-=k;
			k>>=1;
		}
		j+=k;
	}
	for(unsigned l=2;l<=n;l<<=1){//蝶形运算
		double arg=2*PI*rev/l;
		comp wn={cos(arg),sin(arg)};
		for(unsigned i=0;i<n;i+=l){
			comp w={1,0};
			for(unsigned j=0;j<(l>>1);j++){
				comp f1=f[i+j];
				comp f2=f[i+j+(l>>1)];
				f[i+j]=f1+w*f2;
				f[i+j+(l>>1)]=f1-w*f2;
				w=w*wn;
			}
		}
	}
	if(!~rev)
		for(unsigned i=0;i<n;i++)
			f[i]=f[i]/n;
}
//********高精度整数类
#define BASE 100//因为FFT的精度问题严重，我们只压2位
template<const unsigned Size>
class bigint{
private:
	unsigned len;
	int num[Size];
	void init(){
		memset(num,0,sizeof(num));
		len=1;
	}
	bool abs_greater_equal(const bigint &a)const{
		if(len!=a.len)
			return len>a.len;
		for(int i=len;i;i--)
			if(num[i]!=a.num[i])
				return num[i]>a.num[i];
		return 1;
	}
public:
	bigint(){
		init();
	}
	void get_num(std::string s){
		init();
		int f=0;
		unsigned slen=s.length();
		if(s[0]=='-')
			num[0]=f=1;
		len=0;
		unsigned temp=0,w=1;
		for(int i=slen-1;i>=f;i--){
			temp+=(s[i]^48)*w;
			w=(w<<1)+(w<<3);
			if(w==BASE||i==f){
				num[++len]=(int)temp;
				temp=0;
				w=1;
			}
		}
		if(temp||len==0)
			num[++len]=temp;
	}
	bool operator<(const bigint &a)const{
		if(num[0]&&!a.num[0])
			return 1;
		if(!num[0]&&a.num[0])
			return 0;
		if(num[0]){
			if(len!=a.len)
				return len>a.len;
			for(int i=len;i;i--)
				if(num[i]!=a.num[i])
					return num[i]>a.num[i];
		}
		else{
			if(len!=a.len)
				return len<a.len;
			for(int i=len;i;i--)
				if(num[i]!=a.num[i])
					return num[i]<a.num[i];
		}
		return 0;
	}
	bigint operator+(const bigint &a)const{
		bigint res;
		if(len==1&&num[1]==0){
			res=a;
			return res;
		}
		if(a.len==1&&a.num[1]==0){
			res=*this;
			return res;
		}
		if(num[0]==a.num[0]){
			res.num[0]=num[0];
			unsigned len_sum=1;
			while(len_sum<len+a.len)
				len_sum<<=1;
			comp *fa=new comp[len_sum]();
			comp *fb=new comp[len_sum]();
			for(unsigned i=0;i<len;i++)
				fa[i]={(double)num[i+1],0};
			for(unsigned i=0;i<a.len;i++)
				fb[i]={(double)a.num[i+1],0};
			FFT(fa,len_sum,1);
			FFT(fb,len_sum,1);
			for(unsigned i=0;i<len_sum;i++)
				fa[i]=fa[i]+fb[i];
			FFT(fa,len_sum,-1);
			res.len=Max(len,a.len);
			ll temp=0;
			for(unsigned i=0;i<res.len;i++){
				ll val=(ll)round(fa[i].real)+temp;
				res.num[i+1]=(int)(val%BASE);
				temp=val/BASE;
			}
			if(temp)
				res.num[++res.len]=temp;
			while(res.len>1&&res.num[res.len]==0)
				res.len--;
			delete[] fa;
			delete[] fb;
		}
		else{
			if(abs_greater_equal(a)){
				res.num[0]=num[0];
				unsigned len_sum=1;
				while(len_sum<len+a.len)
					len_sum<<=1;
				comp *fa=new comp[len_sum]();
				comp *fb=new comp[len_sum]();
				for(unsigned i=0;i<len;i++)
					fa[i]={(double)num[i+1],0};
				for(unsigned i=0;i<a.len;i++)
					fb[i]={(double)a.num[i+1],0};
				FFT(fa,len_sum,1);
				FFT(fb,len_sum,1);
				for(unsigned i=0;i<len_sum;i++)
					fa[i]=fa[i]-fb[i];
				FFT(fa,len_sum,-1);
				res.len=Max(len,a.len);
				ll temp=0;
				for(unsigned i=0;i<res.len;i++){
					ll val=(ll)round(fa[i].real)+temp;
					if(val<0){
						val+=BASE;
						temp=-1;
					}
					else
						temp=0;//借位
					res.num[i+1]=(int)(val%BASE);
				}
				if(temp)
					res.num[++res.len]=temp;
				while(res.len>1&&res.num[res.len]==0)
					res.len--;
				delete[] fa;
				delete[] fb;
			}
			else{
				res.num[0]=a.num[0];
				unsigned len_sum=1;
				while(len_sum<len+a.len)
					len_sum<<=1;
				comp *fa=new comp[len_sum]();
				comp *fb=new comp[len_sum]();
				for(unsigned i=0;i<len;i++)
					fa[i]={(double)num[i+1],0};
				for(unsigned i=0;i<a.len;i++)
					fb[i]={(double)a.num[i+1],0};
				FFT(fa,len_sum,1);
				FFT(fb,len_sum,1);
				for(unsigned i=0;i<len_sum;i++)
					fa[i]=fb[i]-fa[i];
				FFT(fa,len_sum,-1);
				res.len=Max(len,a.len);
				ll temp=0;
				for(unsigned i=0;i<res.len;i++){
					ll val=(ll)round(fa[i].real)+temp;
					if(val<0){
						val+=BASE;
						temp=-1;
					}
					else
						temp=0;
					res.num[i+1]=(int)(val%BASE);
				}
				if(temp)
					res.num[++res.len]=temp;
				while(res.len>1&&res.num[res.len]==0)
					res.len--;
				delete[] fa;
				delete[] fb;
			}
			if(res.len==1&&res.num[1]==0)
				res.num[0]=0;
		}
		return res;
	}
	bigint operator*(const bigint &a)const{
		bigint res;
		if((len==1&&num[1]==0)||(a.len==1&&a.num[1]==0))
			return res;
		res.num[0]=num[0]^a.num[0];
		unsigned len_sum=1;
		while(len_sum<len+a.len)
			len_sum<<=1;
		comp *fa=new comp[len_sum]();
		comp *fb=new comp[len_sum]();
		for(unsigned i=0;i<len;i++)
			fa[i]={(double)num[i+1],0};
		for(unsigned i=0;i<a.len;i++)
			fb[i]={(double)a.num[i+1],0};
		FFT(fa,len_sum,1);
		FFT(fb,len_sum,1);
		for(unsigned i=0;i<len_sum;i++)
			fa[i]=fa[i]*fb[i];
		FFT(fa,len_sum,-1);
		res.len=len+a.len;
		ll temp=0;
		for(unsigned i=0;i<res.len;i++){
			ll val=(ll)(fa[i].real+0.5)+temp;
			res.num[i+1]=(int)(val%BASE);
			temp=val/BASE;
		}
		if(temp)
			res.num[++res.len]=temp;
		while(res.len>1&&res.num[res.len]==0)
			res.len--;
		delete[] fa;
		delete[] fb;
		return res;
	}
	void read(){
		init();
		std::string s;
		char ch=getchar();
		while(ch<'0'||ch>'9'){
			if(ch=='-')
				s.push_back('-');
			ch=getchar();
		}
		while(ch>='0'&&ch<='9'){
			s.push_back(ch);
			ch=getchar();
		}
		get_num(s);
	}
	void print(){
		if(num[0])
			putchar('-');
		bool leading_zero=1;
		for(int i=len;i;i--){
			if(leading_zero)
				printf("%d",num[i]);
			else
				printf("%02d",num[i]);
			leading_zero=0;
		}
		putchar('\n');
		return;
	}
};
//********程序主体
const int N=1<<10,M=100;
int n,m;
bigint<114514> a,b,c;
int main(){
	a.read();
	b.read();
	c=a+b;
	c.print();
	return 0;
}