高精度加法的使用与实践

高精度加法的用途在于将原本long long int类型不支持的多位数运算通过字符串的方式变为可能。高精度加法是高精度算法中较为简单与常用的算法，实现的方式也较多，例如分段相加，或像小学竖式运算那样每一位都进行相加，逢十进一，或是使用神奇的hugeint（没用过，也许好用）。

主要考验代码实现能力与细节处理，难度大约为普及组水平，没有太高的思维难度。

以下代码为300位自然数范围内的加法运算：

//c++ High precision Addition
//#pragma GCC optimize(3, "Ofast", "inline")
#include <bits/stdc++.h>
using namespace std;
 
const long long int High_Precision_Size = 300;
const int _null = 0;
int Result[High_Precision_Size];
 
 
class High_Precision
{
	private:
		int Answer[High_Precision_Size];
	public:
		virtual inline int Addition(char NumArr_A[], char NumArr_B[]) {
			int NumSize_A = strlen(NumArr_A);
			int NumSize_B = strlen(NumArr_B);
			int Num_A[High_Precision_Size];
			int Num_B[High_Precision_Size];
			memset(Num_A , _null, sizeof(Num_A) );
			memset(Num_B , _null, sizeof(Num_B) );
			memset(Answer, _null, sizeof(Answer));
	
			for(int i = 0; i < NumSize_A; i++)
				Num_A[i] = NumArr_A[NumSize_A - i - 1] - '0';
			for(int i = 0; i < NumSize_B; i++)
				Num_B[i] = NumArr_B[NumSize_B - i - 1] - '0';
			int Maxlen = max(NumSize_A, NumSize_B) + 2;
	
			for(int i = 0; i < Maxlen; i++) {
				Answer[i] += Num_A[i] + Num_B[i];
				if(Answer[i] >= 10) {
					Answer[i+1] += Answer[i] / 10;
					Answer[i] %= 10;
				} 
			}
			int ZeroLock = 0;
			int node = 0;
			for(int i = Maxlen; i >= 0; i--) {
				if(Answer[i] != 0) {
					ZeroLock = i;
					break;
				}
			}
			for(int i = ZeroLock; i >= 0; i--)
				Result[node++] = Answer[i];
			
			for(int i = 0; i < node >> 1; i++)
				swap(Result[i], Result[node/2 - i - 1]);
			return node;
		}
		
}High_Precision;
 
inline void work(void);
 
int main(void) {
    ios::sync_with_stdio(false);
    std::cin.tie(0);
    //freopen(".in", "r", stdin);
    //freopen(".out", "w", stdout);
    work();
    return 0;
}
 
inline void work(void) {
	char Num_A[High_Precision_Size];
	char Num_B[High_Precision_Size];
	memset(Result, _null, sizeof(Result));
	//printf("Please input two numbers.\n");
	cin >> Num_A;
	cin >> Num_B;
	int Maxlen = High_Precision.Addition(Num_A, Num_B);
	for(int i = 0; i < Maxlen; i++) 
		wcout << Result[i];
}