HDU 1047 Integer Inquiry 大数相加 string解法

#include <stdio.h>
#include <vector>
#include <string.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <limits.h>
#include <stack>
#include <queue>
#include <set>
#include <map>
using namespace std;

void plusABtoA(string &a, string &b)
{
	string c;
	int n = (int)a.size(), m = (int)b.size(), carry = 0;
	for (int i = n-1, j = m-1; i >= 0 || j >= 0 || carry; i--, j--)
	{
		int an = i>=0? a[i]-'0' : 0;
		int bn = j>=0? b[j]-'0' : 0;
		carry = an+bn+carry;
		c += char(carry%10 + '0');
		carry /= 10;
	}
	reverse(c.begin(), c.end());
	a = c;
}

int main()
{
	int N;
	string a, b;
	cin>>N;
	while (N--)
	{
		cin>>a;		
		if (a == "0")//注意特殊情况
		{
			cout<<a<<endl;
			if (N) cout<<endl;//注意肯爹输出<span style="white-space:pre">	</span>
			continue;
		}
		while (cin>>b && b != "0")
		{
			plusABtoA(a, b);
		}
		cout<<a<<endl;
		if (N) cout<<endl;//注意肯爹输出
	}
	return 0;
}