Ural1014-Product of Digits

#include <cstdio>
#include <vector>

std::vector<int> v;

int main(int argc, char const *argv[]) {
int n;
while (scanf("%d", &n) == 1) {
if (n == 0) {
printf("10\n");
} else if (n < 10) {
printf("%d\n", n);
} else {
bool ok = true;
while (n != 1) {
ok = false;
for (int i = 9; i >= 2; i--) {
if (n % i == 0) {
v.push_back(i);
n /= i;
ok = true;
break;
}
}
if (!ok) {
printf("-1\n");
break;
}
}
if (ok) {
for (int i = v.size() - 1; i >= 0; i--) {
printf("%d", v[i]);
}
putchar('\n');
}
}
}
return 0;
}