string largestTimeFromDigits(vector<int>& A) {
for (int i = 0; i < 4; i++)
for (int j = 0; j < 4; j++)if (j != i)
for (int k = 0; k < 4; k++)if (k != i && k != j) {
int hours = 10 * A[i] + A[j];
int mins = 10 * A[k] + A[l];
if (hours < 24 && mins < 60)
res = max(res, hours * 60 + mins);
sprintf(c, "%.2d:%.2d", res / 60, res % 60);