[Zerojudge]a021: 大數運算

利用大數四則運算即可解此題。

P.S. 雖然輸入都是正整數，但減法會出現負數。

[C++](12ms, 814KB)

	#include<iostream>
	using namespace std;
	class bignum
	{
	public:
	int num[1000];
	int digit;
	int negative;
	bignum()
	{
	digit = 1;
	for( int i = 0 ; i < 1000 ; i++ )
	num[i] = 0;
	negative = 0;
	}
	bignum( string s )
	{
	digit = s.length();
	for( int i = 0 ; i < s.length() ; i++ )
	num[i] = s[s.length()-i-1] - '0';
	for( int i = s.length() ; i < 1000 ; i++ )
	num[i] = 0;
	negative = 0;
	}
	bignum operator+( bignum x )
	{
	bignum ans;
	int max_digit = max( digit, x.digit );
	for( int i = 0 ; i < max_digit ; i++ )
	{
	ans.num[i] += num[i] + x.num[i];
	ans.num[i+1] += ans.num[i] / 10;
	ans.num[i] %= 10;
	}
	ans.digit = max_digit+1;
	while( !ans.num[ans.digit] && ans.digit >= 0 )
	ans.digit--;
	if( ans.digit < 1 )
	ans.digit = 1;
	else
	ans.digit++;
	return ans;
	}
	bignum operator-( bignum x )
	{
	bignum ans;
	int max_digit = max( digit, x.digit );
	if( *this >= x )
	{
	for( int i = 0 ; i < max_digit ; i++ )
	{
	ans.num[i] = num[i] - x.num[i];
	}
	}
	else
	{
	for( int i = 0 ; i < max_digit ; i++ )
	{
	ans.num[i] = x.num[i] - num[i];
	}
	ans.negative = 1;
	}
	for( int i = 0 ; i < max_digit ; i++ )
	{
	if( ans.num[i] < 0 )
	{
	ans.num[i+1]--;
	ans.num[i] += 10;
	}
	}
	ans.digit = max_digit;
	while( !ans.num[ans.digit] && ans.digit >= 0 )
	ans.digit--;
	if( ans.digit < 1 )
	ans.digit = 1;
	else
	ans.digit++;
	return ans;
	}
	bignum operator*( bignum x )
	{
	bignum ans;
	for( int i = 0 ; i < digit ; i++ )
	for( int j = 0 ; j < x.digit ; j++ )
	ans.num[i+j] += num[i] * x.num[j];
	for( int i = 0 ; i < digit+x.digit+1 ; i++ )
	{
	ans.num[i+1] += ans.num[i] / 10;
	ans.num[i] %= 10;
	}
	ans.digit = digit+x.digit+1;
	while( !ans.num[ans.digit] && ans.digit >= 0 )
	ans.digit--;
	if( ans.digit < 1 )
	ans.digit = 1;
	else
	ans.digit++;
	return ans;
	}
	bignum operator*( int x )
	{
	bignum ans;
	for( int i = 0 ; i < digit ; i++ )
	ans.num[i] += num[i] * x;
	for( int i = 0 ; i < 998 ; i++ )
	{
	ans.num[i+1] += ans.num[i] / 10;
	ans.num[i] %= 10;
	}
	ans.digit = 999;
	while( !ans.num[ans.digit] && ans.digit >= 0 )
	ans.digit--;
	if( ans.digit < 1 )
	ans.digit = 1;
	else
	ans.digit++;
	return ans;
	}
	bool operator>=( bignum x )
	{
	if( digit > x.digit )
	return true;
	if( digit < x.digit )
	return false;
	for( int i = digit ; i >= 0 ; i-- )
	if( num[i] > x.num[i] )
	return true;
	else if( num[i] < x.num[i] )
	return false;
	return true;
	}
	bignum operator/( bignum x )
	{
	bignum temp("0");
	bignum ans;
	for( int i = digit-1 ; i >= 0 ; i-- )
	{
	string tempstr = "";
	tempstr += (char)(num[i]+'0');
	temp = temp * 10 + bignum(tempstr);
	for( int j = 9 ; j > 0 ; j-- )
	{
	if( temp >= x*j )
	{
	temp = temp - x*j;
	ans.num[i] = j;
	break;
	}
	}
	}
	ans.digit = digit;
	while( !ans.num[ans.digit] && ans.digit >= 0 )
	ans.digit--;
	if( ans.digit < 1 )
	ans.digit = 1;
	else
	ans.digit++;
	return ans;
	}
	void print()
	{
	if( negative )
	cout << '-';
	for( int i = digit-1 ; i >= 0 ; i-- )
	cout << num[i];
	cout << endl;
	}
	};
	int main()
	{
	string a, b;
	char ope;
	while( cin >> a >> ope >> b )
	{
	bignum x(a), y(b);
	if( ope == '+' )
	{
	(x+y).print();
	}
	else if( ope == '-' )
	{
	(x-y).print();
	}
	else if( ope == '*' )
	{
	(x*y).print();
	}
	else if( ope == '/' )
	{
	(x/y).print();
	}
	}
	return 0;
	}

view raw Zerojudgea021.cpp hosted with ❤ by GitHub