UVa 10494 If We Were a Child Again (高精度)

10494 - If We Were a Child Again

Time limit: 3.000 seconds

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=97&page=show_problem&problem=1435

“Oooooooooooooooh! If I could do the easy mathematics like my school days!! I can guarantee, that I’d not make any mistake this time!!” Says a smart university student!! But his teacher even smarter – “Ok! I’d assign you such projects in your software lab. Don’t be so sad.” “Really!!” - the students feels happy. And he feels so happy that he cannot see the smile in his teacher’s face.
The Problem   The first project for the poor student was to make a calculator that can just perform the basic arithmetic operations.   But like many other university students he doesn’t like to do any project by himself. He just wants to collect programs from here and there. As you are a friend of him, he asks you to write the program. But, you are also intelligent enough to tackle this kind of people. You agreed to write only the (integer) division and mod (% in C/C++) operations for him.
Input Input is a sequence of lines. Each line will contain an input number. One or more spaces. A sign (division or mod). Again spaces. And another input number. Both the input numbers are non-negative integer. The first one may be arbitrarily long. The second number n will be in the range (0 < n < 231).
Output A line for each input, each containing an integer. See the sample input and output. Output should not contain any extra space.
Sample Input 110 / 100 99 % 10 2147483647 / 2147483647 2147483646 % 2147483647
Sample Output 1 9 1 2147483646

完整代码：

/*0.019s*/

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 1000;///不要开太小了！

char numstr[maxn], numstr2[maxn];

struct bign
{
	int len, s[maxn];

	bign()
	{
		memset(s, 0, sizeof(s));
		len = 1;
	}

	bign(int num)
	{
		*this = num;
	}

	bign(const char* num)
	{
		*this = num;
	}

	bign operator = (const int num)
	{
		char s[maxn];
		sprintf(s, "%d", num);
		*this = s;
		return *this;
	}

	bign operator = (const char* num)
	{
		len = strlen(num);
		for (int i = 0; i < len; i++) s[i] = num[len - i - 1] & 15;
		return *this;
	}

	///输出
	const char* str() const
	{
		if (len)
		{
			for (int i = 0; i < len; i++)
				numstr[i] = '0' + s[len - i - 1];
			numstr[len] = '\0';
		}
		else strcpy(numstr, "0");
		return numstr;
	}

	///去前导零
	void clean()
	{
		while (len > 1 && !s[len - 1]) len--;
	}

	///加
	bign operator + (const bign& b) const
	{
		bign c;
		c.len = 0;
		for (int i = 0, g = 0; g || i < max(len, b.len); i++)
		{
			int x = g;
			if (i < len) x += s[i];
			if (i < b.len) x += b.s[i];
			c.s[c.len++] = x % 10;
			g = x / 10;
		}
		return c;
	}

	///减
	bign operator - (const bign& b) const
	{
		bign c;
		c.len = 0;
		for (int i = 0, g = 0; i < len; i++)
		{
			int x = s[i] - g;
			if (i < b.len) x -= b.s[i];
			if (x >= 0) g = 0;
			else
			{
				g = 1;
				x += 10;
			}
			c.s[c.len++] = x;
		}
		c.clean();
		return c;
	}

	///乘
	bign operator * (const bign& b) const
	{
		bign c;
		c.len = len + b.len;
		for (int i = 0; i < len; i++)
			for (int j = 0; j < b.len; j++)
				c.s[i + j] += s[i] * b.s[j];
		for (int i = 0; i < c.len - 1; i++)
		{
			c.s[i + 1] += c.s[i] / 10;
			c.s[i] %= 10;
		}
		c.clean();
		return c;
	}

	///除
	bign operator / (const bign &b) const
	{
		bign ret, cur = 0;
		ret.len = len;
		for (int i = len - 1; i >= 0; i--)
		{
			cur = cur * 10;
			cur.s[0] = s[i];
			while (cur >= b)
			{
				cur -= b;
				ret.s[i]++;
			}
		}
		ret.clean();
		return ret;
	}

	///模、余
	bign operator % (const bign &b) const
	{
		bign c = *this / b;
		return *this - c * b;
	}

	bool operator < (const bign& b) const
	{
		if (len != b.len) return len < b.len;
		for (int i = len - 1; i >= 0; i--)
			if (s[i] != b.s[i]) return s[i] < b.s[i];
		return false;
	}

	bool operator > (const bign& b) const
	{
		return b < *this;
	}

	bool operator <= (const bign& b) const
	{
		return !(b < *this);
	}

	bool operator >= (const bign &b) const
	{
		return !(*this < b);
	}

	bool operator == (const bign& b) const
	{
		return !(b < *this) && !(*this < b);
	}

	bool operator != (const bign &a) const
	{
		return *this > a || *this < a;
	}

	bign operator += (const bign &a)
	{
		*this = *this + a;
		return *this;
	}

	bign operator -= (const bign &a)
	{
		*this = *this - a;
		return *this;
	}

	bign operator *= (const bign &a)
	{
		*this = *this * a;
		return *this;
	}

	bign operator /= (const bign &a)
	{
		*this = *this / a;
		return *this;
	}

	bign operator %= (const bign &a)
	{
		*this = *this % a;
		return *this;
	}
} a, b;

int main(void)
{
	char op;
	while (~scanf("%s %c %s", numstr, &op, numstr2))
	{
		a = numstr, b = numstr2;
		puts(op == '/' ? (a / b).str() : (a % b).str());
	}
	return 0;
}