Rt.

代码如下。

#include <bits/stdc++.h>
using namespace std;
int main(){
	string c1,c2;
	int B;
	int n1[10005] = {0},n2[10005] = {0},n3[10005] = {0};
	cin >> B >> c1 >> c2;
	int len1 = c1.length();
	int len2 = c2.length();
	for (int i = 0;i < len1;i++){
		if (c1[len1 - i - 1] >= '0' && c1[len1 - i - 1] <= '9') n1[i] = c1[len1 - i - 1] - '0';
		else n1[i] = c1[len1 - i - 1] - 'A' + 10;
	}
	for (int i = 0;i < len2;i++){
		if (c2[len2 - i - 1] >= '0' && c2[len2 - i - 1] <= '9') n2[i] = c2[len2 - i - 1] - '0';
		else n2[i] = c2[len2 - i - 1] - 'A' + 10;
	}
	int len3 = max(len1,len2);
	for (int i = 0;i < len3;i++){
		n3[i] += n1[i] + n2[i];
		if (n3[i] > B - 1){
			n3[i + 1] += 1;
			n3[i] %= B;
		}
	}
	if (n3[len3] ) len3 += 1;
	for (int i = len3 - 1;i >= 0;i--){
		if (n3[i] >= '0' && n3[i] <= '9') cout << n3[i];
		else cout << (char)(n3[i] + 10 - 'A');
	} 
	return 0;
}