1 #include<stdio.h>
 2 #include<string.h>
 3 
 4 char str[55][1005];
 5 char ans[1005];
 6 
 7 int findMax(int a, int b, int c, int d)
 8 { 
 9     int tmp[4] = {a, b, c, d};
10     int max = 0;
11     for(int i = 0; i < 4; i++)
12     {
13         if(max < tmp[i])
14             max = tmp[i];
15     }
16     return max;
17     
18 }
19 int main()
20 {
21     int T, m, n, count;
22     scanf("%d", &T);
23     while(T--)
24     {
25         count = 0;
26         scanf("%d %d", &m, &n);
27         getchar();    //吃掉换行符
28         for(int i = 0; i < m; i++)
29         {
30             for(int j = 0; j < n; j++)
31             {
32                 scanf("%c", &str[i][j]);
33             }
34             getchar();    //吃掉换行符
35         }
36         //统计每一列字符出现的字数，找到最大的，若一样优先'A'
37         for(int i = 0; i < n; i++)
38         {
39             int a = 0, c = 0, g = 0, t = 0;
40             for(int j = 0; j < m; j++)
41             {
42                 if(str[j][i] == 'A')
43                     a++;
44                 if(str[j][i] == 'C')
45                     c++;
46                 if(str[j][i] == 'G')
47                     g++;
48                 if(str[j][i] == 'T')
49                     t++;
50             }
51             int max = findMax(a, c, g, t);
52             if(a == max)
53             {
54                 ans[i] = 'A';
55                 continue;
56             }    
57             if(c == max)
58             {
59                 ans[i] = 'C';
60                 continue;
61             }    
62             if(g == max)
63             {
64                 ans[i] = 'G';
65                 continue;
66             }
67             if(t == max)
68             {
69                 ans[i] = 'T';
70                 continue;
71             }    
72         }
73         //计算总Hamming
74         for(int i = 0; i < m; i++)
75         {
76             for(int j = 0; j < n; j++)
77             {
78                 if(ans[j] != str[i][j])
79                     count++;    
80             }    
81         } 
82         for(int i = 0; i < n; i++)
83             printf("%c", ans[i]);
84         printf("\n");
85         printf("%d\n", count);
86     }    
87 }