题解 | 还是A+B

#include<bits/stdc++.h>
using namespace std;


int main() {
		int a, b, k;
		scanf("%d %d %d", &a, &b, &k);
		if (k == 0) {
			printf("%d\n", -1);
			return 0;
		}
		int temp1 = a;
		int temp2 = b;
		int temp = k;
		vector<int> v;
		vector<int> v2;
		while (temp > 0) {
			v.push_back(temp1 % 10);
			temp1 /= 10;
			temp--;
		}
		temp = k;
		while (temp > 0) {
			v2.push_back(temp2 % 10);
			temp2 /= 10;
			temp--;
		}
		int count = 0;
		for (int i = 0; i <= v.size()-1; i++) {
			if (v[i] == v2[i]) {
				count++;
			}
		}
		
		if (count == k)
			printf("%d\n", -1);
		else
			printf("%d\n", a + b);
		return 0;
	
}