UVA 485、424、495、324 大整数
题目：
分析：大整数的乘法与加法 推荐算法分析 ”程序员小灰“微信平台 文章。（关注他微信公众号后，点击右上角「…」，再点击「全部消息」，搜索「大整数」，完成）
说明：定定定 c++编写了一个大整数类来解决这些题。当然，大整数类 并不完善，日后继续学习时，找机会完善。
大整数代码
#include
bigInteger(const bigInteger &A)
{
this->len=A.len;
if(len!=0)
{
this->arrayInt=new int[len];
for(unsigned int i=0; i<len; i++)
{
(this->arrayInt)[i]=(A.arrayInt)[i];
}
}
}
bigInteger& operator=(const bigInteger & A)
{
this->len=A.len;
if(len!=0)
{
this->arrayInt=new int[len];
for(unsigned int i=0; i<len; i++)
{
(this->arrayInt)[i]=(A.arrayInt)[i];
}
}
return *this;
}
void operator += (const bigInteger &A)
{
if(A.arrayInt!=NULL && this->arrayInt!=NULL)
{
unsigned int maxlength=max(this->len,A.len);
unsigned int minlength=min(this->len,A.len);
bigInteger result(maxlength);
result.arrayInt[0]=0;
//做加法
for(unsigned int i=0; i<maxlength; i++)
{
int temp;
if(i<minlength)
temp=this->arrayInt[i]+A.arrayInt[i]+result.arrayInt[i];
else
{
if(A.len==minlength)
temp=this->arrayInt[i]+result.arrayInt[i];
else if(this->len==minlength)
temp=A.arrayInt[i]+result.arrayInt[i];
}
result.arrayInt[i]=temp%10;
result.arrayInt[i+1]=temp/10;
}
//程序健壮性
if(result.arrayInt[maxlength]!=0)
{
result.len++;
}
else {}//else时，不改变result.len
*this=result;
}
else if(A.arrayInt!=NULL && this->arrayInt==NULL)
{
*this=A;
}
}
friend istream & operator >>(istream & in,bigInteger &A);
friend ostream & operator <<(ostream & out,const bigInteger &A);
friend bigInteger operator+(const bigInteger A,const bigInteger B);
friend bigInteger operator*(const bigInteger A,const bigInteger B);
//适配题目的函数
int *getarrayInt()
{
return arrayInt;
}
int getLen()
{
return len;
}
};
istream & operator >>(istream & in,bigInteger &A)
{
string s;
in>>s;
A=bigInteger(s);//为什么这样不行？？？过了，应该是当时，没重载<<
/* if(A.arrayInt!=NULL)
{
delete []A.arrayInt;
}
A.len=s.length();
A.arrayInt=new int[A.len];
for(unsigned int i=0; i
return in;
}
ostream & operator <<( ostream & out,const bigInteger &A)// cout<<(A+B);
{
for(unsigned int i=0; i<A.len; i++)
out<<A.arrayInt[A.len-1-i];
return out;
}
bigInteger operator+(const bigInteger A,const bigInteger B)
{
if(A.arrayInt!=NULL && B.arrayInt!=NULL)
{
unsigned int maxlength=max(B.len,A.len);
unsigned int minlength=min(B.len,A.len);
bigInteger result(maxlength);
result.arrayInt[0]=0;
for(unsigned int i=0; i<maxlength; i++)
{
int temp;
if(i<minlength)
temp=B.arrayInt[i]+A.arrayInt[i]+result.arrayInt[i];
else
{
if(B.len==minlength)
temp=A.arrayInt[i]+result.arrayInt[i];
else if(A.len==minlength)
temp=B.arrayInt[i]+result.arrayInt[i];
}
result.arrayInt[i]=temp%10;
result.arrayInt[i+1]=temp/10;
}
if(result.arrayInt[maxlength]!=0)
{
result.len++;
}
else {}//else时，不改变result.len
return result;
}
else
{
if(A.arrayInt!=NULL)
return A;
else if(B.arrayInt!=NULL)
return B;
else if(A.arrayInt==NULL &&B.arrayInt==NULL)
return A;
}
}
bigInteger operator*(const bigInteger A,const bigInteger B)
{
if(A.arrayInt!=NULL && B.arrayInt!=NULL)
{
bigInteger result(A.len+B.len) ;
result.arrayInt[0]=0;
for(unsigned int i=0; i<B.len; i++)
{
for(unsigned int j=0; j<A.len; j++)
{
result.arrayInt[i+j]+=A.arrayInt[j]*B.arrayInt[i];
if(result.arrayInt[i+j]>=10)
{
result.arrayInt[i+j+1]+=result.arrayInt[i+j]/10;
result.arrayInt[i+j]=result.arrayInt[i+j]%10;
}
}
}
//确定result.len
int counter=0;
for(unsigned int i=result.len-1; i>=(max(A.len,B.len)-1); i--)
{
if(result.arrayInt[i]==0)
{
counter++;
}
else
break;
}
result.len-=counter;
return result;
}
else
{
if(A.arrayInt!=NULL)
return A;
else if(B.arrayInt!=NULL)
return B;
else if(A.arrayInt==NULL &&B.arrayInt==NULL)
return A;
}
}
UVA 485 Pascal’s Triangle of Death（主函数部分）
杨辉三角 （注意 把数组a写到全局变量，否则可能会Runtimely Error)
bigInteger a[1500],init("1");
int main()
{
int k=1;
bool flag=true;
a[0]=init;
while(flag)
{
bigInteger p,q("0");
if(k!=1) a[k-1]=q;
for(int i=0;i<k;++i)
{
p=a[i];
a[i]=p+q;
if(a[i].getLen()>=61) {flag=false;}//当位数为61时，那一行也要输出
q=p;
}
for(int i=0;i<k;++i)
{
if(i!=0) cout<<' ';
cout<<a[i];
}
cout<<endl;
k++;
}
return 0;
}
UVA 424 Integer Inquiry
整数加法
int main()
{
bigInteger a,b;
while(1)
{
cin>>b;
if(b.getarrayInt()[0]==0&&b.getLen()==1)
break;
else
{
a+=b;
}
}
cout<<a<<endl;
return 0;
}
UVA 495 Fibonacci Freeze
斐波那契数列 （注意第一项从0开始）
bigInteger a[5003]={bigInteger("0"),bigInteger("1"),bigInteger("1")};
int main()
{
for(int j=3;j<=5000;++j)
{
a[j]=a[j-1]+a[j-2];
}
int i;
while(scanf("%d",&i) != EOF)
{
cout<<"The Fibonacci number for "<<i<<" is "<<a[i]<<endl;
}
return 0;
}
UVA 324 Factorial Frequencies
阶乘
bigInteger a[366]= {bigInteger("1")};
int main()
{
for(int i=1; i<366; i++)
{
stringstream ss;
string s;
ss<<i+1;
ss>>s;
bigInteger num(s);
a[i]=a[i-1]*s;
}
int k;
while(cin>>k&&k!=0)
{
int record_count[10]= {0};
for(int i=0; i<a[k-1].getLen(); ++i)
{
int number;
number=(a[k-1].getarrayInt())[i];
switch(number)
{
case 0:
record_count[0]++;
break;
case 1:
record_count[1]++;
break;
case 2:
record_count[2]++;
break;
case 3:
record_count[3]++;
break;
case 4:
record_count[4]++;
break;
case 5:
record_count[5]++;
break;
case 6:
record_count[6]++;
break;
case 7:
record_count[7]++;
break;
case 8:
record_count[8]++;
break;
case 9:
record_count[9]++;
break;
}
}
//输出
printf("%d! --\n",k);
printf("(0) %d (1) %d (2) %d (3) %d (4) %d\n",record_count[0],record_count[1],record_count[2],
record_count[3],record_count[4]);
printf("(5) %d (6) %d (7) %d (8) %d (9) %d\n",record_count[5],record_count[6],record_count[7],
record_count[8],record_count[9]);
}
return 0;
}
查题网站：https://vjudge.net/
分析大整数乘法：
