[BOJ] 9047 : 6174

#include <cstdio>
#include <functional>
#include <algorithm>
using namespace std;

int main() {
    int tc;
    for (scanf("%d", &tc); tc--;) {
        int i, c = 0, a[5], b[5];
        for (i = 0; i < 4; i++) scanf(" %1d", &a[i]);
        while (a[0] != 6 || a[1] != 1 || a[2] != 7 || a[3] != 4) {
            b[0] = a[0], b[1] = a[1], b[2] = a[2], b[3] = a[3];
            sort(a, a + 4, greater<int>());
            sort(b, b + 4);
            for (i = 3; i >= 0; i--) {
                a[i] -= b[i];
                if (a[i] < 0) a[i] += 10, a[i - 1]--;
            }
            c++;
        }
        printf("%d\n", c);
    }

    return 0;
}