大整数类BigInteger
2015-08-09 16:07
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参考资料:《算法竞赛入门经典》
使用C++实现大整数类,并重载了大整数类的=、>>、<<、<、>、+等操作符。
#include <iostream>
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
struct BigInteger
{
static const int BASE = 100000000;
static const int WIDTH = 8;
vector<int> s;
BigInteger operator = (long long num)
{
s.clear();
do
{
s.push_back(num%BASE);
num /= BASE;
}while(num);
return *this;
}
BigInteger operator = (const string &str)
{
s.clear();
int x,len = (str.length()-1) / WIDTH + 1;
for(int i = 0; i < len; i++)
{
int end = str.length() - i * WIDTH;
int begin = max(0, end - WIDTH);
sscanf(str.substr(begin,end - begin).c_str(), "%d", &x);
s.push_back(x);
}
return *this;
}
friend ostream& operator << (ostream &out,const BigInteger &x)
{
out << x.s.back();
for(int i = x.s.size() - 2; i >=0; i--)
{
char buf[20];
sprintf(buf,"%08d",x.s[i]);
for(int j = 0; j < strlen(buf); j++) out << buf[j];
}
return out;
}
friend istream& operator >> (istream &in,BigInteger &x)
{
string s;
if(!(in >> s)) return in;
x = s;
return in;
}
BigInteger operator + (const BigInteger& b) const
{
BigInteger c;
c.s.clear();
for(int i = 0, g = 0; ; i++)
{
if(g == 0 && i >= s.size() && i >= b.s.size()) break;
int x = g;
if(i < s.size()) x += s[i];
if(i < b.s.size()) x += b.s[i];
c.s.push_back(x % BASE);
g = x / BASE;
}
return c;
}
BigInteger operator += (const BigInteger &b)
{
*this = *this + b;
return *this;
}
bool operator < (const BigInteger &b) const
{
if(s.size() != b.s.size()) return s.size() < b.s.size();
for(int i = s.size() - 1; i >= 0; i--)
{
if(s[i] != b.s[i]) return s[i] < b.s[i];
}
return false;
}
bool operator > (const BigInteger &b) const
{
return *this > b;
}
};
int main()
{
BigInteger x;
cin >> x;
cout << x << endl;
int num = 10;
x = num;
cout << x << endl;
string str = "111";
x = str;
cout << x << endl;
BigInteger x1;
x1 = "321312321321313";
BigInteger x2 = x + x1;
cout << x2;
return 0;
}
使用C++实现大整数类,并重载了大整数类的=、>>、<<、<、>、+等操作符。
#include <iostream>
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
struct BigInteger
{
static const int BASE = 100000000;
static const int WIDTH = 8;
vector<int> s;
BigInteger operator = (long long num)
{
s.clear();
do
{
s.push_back(num%BASE);
num /= BASE;
}while(num);
return *this;
}
BigInteger operator = (const string &str)
{
s.clear();
int x,len = (str.length()-1) / WIDTH + 1;
for(int i = 0; i < len; i++)
{
int end = str.length() - i * WIDTH;
int begin = max(0, end - WIDTH);
sscanf(str.substr(begin,end - begin).c_str(), "%d", &x);
s.push_back(x);
}
return *this;
}
friend ostream& operator << (ostream &out,const BigInteger &x)
{
out << x.s.back();
for(int i = x.s.size() - 2; i >=0; i--)
{
char buf[20];
sprintf(buf,"%08d",x.s[i]);
for(int j = 0; j < strlen(buf); j++) out << buf[j];
}
return out;
}
friend istream& operator >> (istream &in,BigInteger &x)
{
string s;
if(!(in >> s)) return in;
x = s;
return in;
}
BigInteger operator + (const BigInteger& b) const
{
BigInteger c;
c.s.clear();
for(int i = 0, g = 0; ; i++)
{
if(g == 0 && i >= s.size() && i >= b.s.size()) break;
int x = g;
if(i < s.size()) x += s[i];
if(i < b.s.size()) x += b.s[i];
c.s.push_back(x % BASE);
g = x / BASE;
}
return c;
}
BigInteger operator += (const BigInteger &b)
{
*this = *this + b;
return *this;
}
bool operator < (const BigInteger &b) const
{
if(s.size() != b.s.size()) return s.size() < b.s.size();
for(int i = s.size() - 1; i >= 0; i--)
{
if(s[i] != b.s[i]) return s[i] < b.s[i];
}
return false;
}
bool operator > (const BigInteger &b) const
{
return *this > b;
}
};
int main()
{
BigInteger x;
cin >> x;
cout << x << endl;
int num = 10;
x = num;
cout << x << endl;
string str = "111";
x = str;
cout << x << endl;
BigInteger x1;
x1 = "321312321321313";
BigInteger x2 = x + x1;
cout << x2;
return 0;
}
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