大数(只能处理正数)
//功能挺全的，以后再作说明吧。
#include <iostream.h>
#include <string.h>
#define DIGIT 4
#define DEPTH 10000
#define MAX 100
typedef int bignum_t[MAX+1];
int read(bignum_t a,istream& is=cin){
char buf[MAX*DIGIT+1],ch;
int i,j;
memset((void*)a,0,sizeof(bignum_t));
if (!(is>>buf)) return 0;
for (a[0]=strlen(buf),i=a[0]/2-1;i>=0;i--)
ch=buf[i],buf[i]=buf[a[0]-1-i],buf[a[0]-1-i]=ch;
for (a[0]=(a[0]+DIGIT-1)/DIGIT,j=strlen(buf);j<a[0]*DIGIT;buf[j++]='0');
for (i=1;i<=a[0];i++)
for (a[i]=0,j=0;j<DIGIT;j++)
a[i]=a[i]*10+buf[i*DIGIT-1-j]-'0';
for (;!a[a[0]]&&a[0]>1;a[0]--);
return 1;
}
void write(const bignum_t a,ostream& os=cout){
int i,j;
for (os<<a[i=a[0]],i--;i;i--)
for (j=DEPTH/10;j;j/=10)
os<<a[i]/j%10;
}
int comp(const bignum_t a,const bignum_t b){
int i;
if (a[0]!=b[0])
return a[0]-b[0];
for (i=a[0];i;i--)
if (a[i]!=b[i])
return a[i]-b[i];
return 0;
}
int comp(const bignum_t a,const int b){
int c[12]={1};
for (c[1]=b;c[c[0]]>=DEPTH;c[c[0]+1]=c[c[0]]/DEPTH,c[c[0]]%=DEPTH,c[0]++);
return comp(a,c);
}
int comp(const bignum_t a,const int c,const int d,const bignum_t b){
int i,t=0,O=-DEPTH*2;
if (b[0]-a[0]<d&&c)
return 1;
for (i=b[0];i>d;i--){
t=t*DEPTH+a[i-d]*c-b[i];
if (t>0) return 1;
if (t<O) return 0;
}
for (i=d;i;i--){
t=t*DEPTH-b[i];
if (t>0) return 1;
if (t<O) return 0;
}
return t>0;
}
void add(bignum_t a,const bignum_t b){
int i;
for (i=1;i<=b[0];i++)
if ((a[i]+=b[i])>=DEPTH)
a[i]-=DEPTH,a[i+1]++;
if (b[0]>=a[0])
a[0]=b[0];
else
for (;a[i]>=DEPTH&&i<a[0];a[i]-=DEPTH,i++,a[i]++);
a[0]+=(a[a[0]+1]>0);
}
void add(bignum_t a,const int b){
int i=1;
for (a[1]+=b;a[i]>=DEPTH&&i<a[0];a[i+1]+=a[i]/DEPTH,a[i]%=DEPTH,i++);
for (;a[a[0]]>=DEPTH;a[a[0]+1]=a[a[0]]/DEPTH,a[a[0]]%=DEPTH,a[0]++);
}
void sub(bignum_t a,const bignum_t b){
int i;
for (i=1;i<=b[0];i++)
if ((a[i]-=b[i])<0)
a[i+1]--,a[i]+=DEPTH;
for (;a[i]<0;a[i]+=DEPTH,i++,a[i]--);
for (;!a[a[0]]&&a[0]>1;a[0]--);
}
void sub(bignum_t a,const int b){
int i=1;
for (a[1]-=b;a[i]<0;a[i+1]+=(a[i]-DEPTH+1)/DEPTH,a[i]-=(a[i]-DEPTH+1)/DEPTH*DEPTH,i++);
for (;!a[a[0]]&&a[0]>1;a[0]--);
}
void sub(bignum_t a,const bignum_t b,const int c,const int d){
int i,O=b[0]+d;
for (i=1+d;i<=O;i++)
if ((a[i]-=b[i-d]*c)<0)
a[i+1]+=(a[i]-DEPTH+1)/DEPTH,a[i]-=(a[i]-DEPTH+1)/DEPTH*DEPTH;
for (;a[i]<0;a[i+1]+=(a[i]-DEPTH+1)/DEPTH,a[i]-=(a[i]-DEPTH+1)/DEPTH*DEPTH,i++);
for (;!a[a[0]]&&a[0]>1;a[0]--);
}
void mul(bignum_t c,const bignum_t a,const bignum_t b){
int i,j;
memset((void*)c,0,sizeof(bignum_t));
for (c[0]=a[0]+b[0]-1,i=1;i<=a[0];i++)
for (j=1;j<=b[0];j++)
if ((c[i+j-1]+=a[i]*b[j])>=DEPTH)
c[i+j]+=c[i+j-1]/DEPTH,c[i+j-1]%=DEPTH;
for (c[0]+=(c[c[0]+1]>0);!c[c[0]]&&c[0]>1;c[0]--);
}
void mul(bignum_t a,const int b){
int i;
for (a[1]*=b,i=2;i<=a[0];i++){
a[i]*=b;
if (a[i-1]>=DEPTH)
a[i]+=a[i-1]/DEPTH,a[i-1]%=DEPTH;
}
for (;a[a[0]]>=DEPTH;a[a[0]+1]=a[a[0]]/DEPTH,a[a[0]]%=DEPTH,a[0]++);
for (;!a[a[0]]&&a[0]>1;a[0]--);
}
void mul(bignum_t b,const bignum_t a,const int c,const int d){
int i;
memset((void*)b,0,sizeof(bignum_t));
for (b[0]=a[0]+d,i=d+1;i<=b[0];i++)
if ((b[i]+=a[i-d]*c)>=DEPTH)
b[i+1]+=b[i]/DEPTH,b[i]%=DEPTH;
for (;b[b[0]+1];b[0]++,b[b[0]+1]=b[b[0]]/DEPTH,b[b[0]]%=DEPTH);
for (;!b[b[0]]&&b[0]>1;b[0]--);
}
void div(bignum_t c,bignum_t a,const bignum_t b){
int h,l,m,i;
memset((void*)c,0,sizeof(bignum_t));
c[0]=(b[0]<a[0]+1)?(a[0]-b[0]+2):1;
for (i=c[0];i;sub(a,b,c[i]=m,i-1),i--)
for (h=DEPTH-1,l=0,m=(h+l+1)>>1;h>l;m=(h+l+1)>>1)
if (comp(b,m,i-1,a)) h=m-1;
else l=m;
for (;!c[c[0]]&&c[0]>1;c[0]--);
c[0]=c[0]>1?c[0]:1;
}
void div(bignum_t a,const int b,int& c){
int i;
for (c=0,i=a[0];i;c=c*DEPTH+a[i],a[i]=c/b,c%=b,i--);
for (;!a[a[0]]&&a[0]>1;a[0]--);
}
void sqrt(bignum_t b,bignum_t a){
int h,l,m,i;
memset((void*)b,0,sizeof(bignum_t));
for (i=b[0]=(a[0]+1)>>1;i;sub(a,b,m,i-1),b[i]+=m,i--)
for (h=DEPTH-1,l=0,b[i]=m=(h+l+1)>>1;h>l;b[i]=m=(h+l+1)>>1)
if (comp(b,m,i-1,a)) h=m-1;
else l=m;
for (;!b[b[0]]&&b[0]>1;b[0]--);
for (i=1;i<=b[0];b[i++]>>=1);
}
int length(const bignum_t a){
int t,ret;
for (ret=(a[0]-1)*DIGIT,t=a[a[0]];t;t/=10,ret++);
return ret>0?ret:1;
}
int digit(const bignum_t a,const int b){
int i,ret;
for (ret=a[(b-1)/DIGIT+1],i=(b-1)%DIGIT;i;ret/=10,i--);
return ret%10;
}
int zeronum(const bignum_t a){
int ret,t;
for (ret=0;!a[ret+1];ret++);
for (t=a[ret+1],ret*=DIGIT;!(t%10);t/=10,ret++);
return ret;
}
void comp(int* a,const int l,const int h,const int d){
int i,j,t;
for (i=l;i<=h;i++)
for (t=i,j=2;t>1;j++)
while (!(t%j))
a[j]+=d,t/=j;
}
void convert(int* a,const int h,bignum_t b){
int i,j,t=1;
memset(b,0,sizeof(bignum_t));
for (b[0]=b[1]=1,i=2;i<=h;i++)
if (a[i])
for (j=a[i];j;t*=i,j--)
if (t*i>DEPTH)
mul(b,t),t=1;
mul(b,t);
}
void combination(bignum_t a,int m,int n){
int* t=new int[m+1];
memset((void*)t,0,sizeof(int)*(m+1));
comp(t,n+1,m,1);
comp(t,2,m-n,-1);
convert(t,m,a);
delete []t;
}
void permutation(bignum_t a,int m,int n){
int i,t=1;
memset(a,0,sizeof(bignum_t));
a[0]=a[1]=1;
for (i=m-n+1;i<=m;t*=i++)
if (t*i>DEPTH)
mul(a,t),t=1;
mul(a,t);
}
#define SGN(x) ((x)>0?1:((x)<0?-1:0))
#define ABS(x) ((x)>0?(x):-(x))
int read(bignum_t a,int &sgn,istream& is=cin){
char str[MAX*DIGIT+2],ch,*buf;
int i,j;
memset((void*)a,0,sizeof(bignum_t));
if (!(is>>str)) return 0;
buf=str,sgn=1;
if (*buf=='-') sgn=-1,buf++;
for (a[0]=strlen(buf),i=a[0]/2-1;i>=0;i--)
ch=buf[i],buf[i]=buf[a[0]-1-i],buf[a[0]-1-i]=ch;
for (a[0]=(a[0]+DIGIT-1)/DIGIT,j=strlen(buf);j<a[0]*DIGIT;buf[j++]='0');
for (i=1;i<=a[0];i++)
for (a[i]=0,j=0;j<DIGIT;j++)
a[i]=a[i]*10+buf[i*DIGIT-1-j]-'0';
for (;!a[a[0]]&&a[0]>1;a[0]--);
if (a[0]==1&&!a[1]) sgn=0;
return 1;
}