題目傳送門

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>
#define MAXN 1010
#define MAXM 55
using namespace std;
string str[MAXM];
//char s[MAXN];
int main(void)
{
	int m, n;
	int T;

	scanf("%d", &T);
	while (T--)
	{
		scanf("%d%d", &m, &n);
		for (int i = 0; i < m; i++)cin >> str[i];
		int sum = 0;
		for (int i = 0; i < n; i++)
		{
			int num[26] = { 0 };
			int max_num = 0;
			int position = 0;

			for (int j = 0; j < m; j++)num[str[j][i] - 'A']++;
			for (int j = 0; j < 26; j++)
				if (num[j] > max_num)
				{
					max_num = num[j];
					position = j;
				}
			printf("%c", position + 'A');
			sum += m - max_num;
		}
		putchar('\n');
		printf("%d\n", sum);
		
	}


	return 0;
}