struct bignum{
#define base 10000
int a[20000];
bignum(){memset(a,0,sizeof(a));}
inline void init(){memset(a,0,sizeof(a));a[0]=1;a[1]=1;}
inline void read(){
static char s[1000];scanf("%s",s);
int n=strlen(s),len=1;
for(int i=1,k=1;i<=n;i++){
if(k==10000){len++;k=1;}
a[len]+=k*(s[n-i]^48);
k=(k<<1)+(k<<3);
}a[0]=len;
}
inline bignum trans(int b){
bignum ans;
while(b){ans.a[++ans.a[0]]=b%base;b/=base;}
return ans;
}
bignum operator+(const bignum &b){
bignum ans;
for(int i=1,x=0,tmp=0;x||i<=a[0]||i<=b.a[0];++i){
tmp=a[i]+b.a[i]+x;
ans.a[++ans.a[0]]=tmp%base;
x=tmp/base;
}
return ans;
}
bignum operator-(const bignum &b){
bignum ans;
for(int i=1,x=0,tmp=0;i<=a[0];++i){
tmp=a[i]-b.a[i]-x;
if(tmp>=0) x=0;
else tmp+=base,x=1;
ans.a[++ans.a[0]]=tmp;
}
while(ans.a[0]>1&&ans.a[ans.a[0]]==0) ans.a[0]--;
return ans;
}
bignum operator*(const bignum &b){
bignum ans;ans.a[0]=a[0]+b.a[0];
for(int i=1;i<=a[0];++i){
for(int j=1,x=0;x||j<=b.a[0];++j){
ans.a[i+j-1]+=x+a[i]*b.a[j];
x=ans.a[i+j-1]/base;
ans.a[i+j-1]%=base;
}
}
while(ans.a[0]>1&&ans.a[ans.a[0]]==0) ans.a[0]--;
return ans;
}
bignum operator*(const int &b){
bignum ans;
for(int i=1,x=0,tmp=0;x||i<=a[0];++i){
tmp=a[i]*b+x;
ans.a[++ans.a[0]]=tmp%base;
x=tmp/base;
}
return ans;
}
friend bool operator<(const bignum &x,const bignum &y){
if(x.a[0]^y.a[0]) return x.a[0]<y.a[0];
for(int i=x.a[0];i>=1;--i) if(x.a[i]^y.a[i]) return x.a[i]<y.a[i];
return false;
}
friend bool operator>(const bignum &x,const bignum &y){return y<x;}
friend bool operator==(const bignum &x,const bignum &y){return !(x>y)&&!(x<y);}
inline void print(){put_int(a[a[0]]);for(int i=a[0]-1;i>=1;i--)printf("%04d",a[i]);putchar('\n');}
#undef base
};
标签:bignum,高精度,int,压位,return,--,ans,const,模板
From: https://www.cnblogs.com/UNowen/p/17475835.html