LRJ 3-7

#define _CRT_SECURE_NO_WARNINGS 
 
#include <cstdio>
 
int main()
{
    int T;
    int m, n;
    char dna[][]; // 4 <= m <= 50, 4 <= n <= 1000
 
    scanf("%d", &T);
    while (T--) {
        scanf("%d%d", &m, &n);
        for (int i = ; i < m; i++) {
            scanf("%s", dna[i]);
        }
        /*
        for (int i = 0; i < m; i++) {
            printf("%s\n", dna[i]);
        }
        */
        char ans[]; // 4 <= n <= 1000
        int cnt[]; // count for 'A', 'C', 'G', 'T' in a column
        int max;
        char maxChar;
 
        // scan each column, select the character which occurs the most time,
        // if there is a tie, select the lexicographically smaller one
        for (int j = ; j < n; j++){ 
 
            cnt[] = cnt[] = cnt[] = cnt[] = max = ;
 
            for (int i = ; i < m; i++){
                switch (dna[i][j]){
                case 'A': {
                    cnt[]++;
                    if (cnt[] > max || (cnt[] == max && maxChar > 'A')){
                        max = cnt[];
                        maxChar = 'A';
                    }
                    break;
                }
                case 'C': {
                    cnt[]++;
                    if (cnt[] > max || (cnt[] == max && maxChar > 'C')){
                        max = cnt[];
                        maxChar = 'C';
                    }
                    break;
                }
                case 'G': {
                    cnt[]++;
                    if (cnt[] > max || (cnt[] == max && maxChar > 'G')){
                        max = cnt[];
                        maxChar = 'G';
                    }
                    break;
                }
                case 'T': {
                    cnt[]++;
                    if (cnt[] > max){
                        max = cnt[];
                        maxChar = 'T';
                    }
                    break;
                }
                }
 
            }
 
            ans[j] = maxChar;
        }
        ans[n] = '\0';
        printf("%s\n", ans);
 
        // count the total Hamming distance
        int h_dis = ;
        for (int i = ; i < m; i++){
            for (int j = ; j < n; j++){
                if (dna[i][j] != ans[j])
                    h_dis++;
            }
        }
        printf("%d\n", h_dis);
    }
 
    return ;
}