For what is worth:
the closest integer to any given input as shown in the following table can be calculated using Math.ceil or Math.floor depending of the distance between the input and the next integer
+-------+--------+
| input | output |
+-------+--------+
| 1 | 0 |
| 2 | 0 |
| 3 | 5 |
| 4 | 5 |
| 5 | 5 |
| 6 | 5 |
| 7 | 5 |
| 8 | 10 |
| 9 | 10 |
+-------+--------+
private int roundClosest(final int i, final int k) {
int deic = (i % k);
if (deic <= (k / 2.0)) {
return (int) (Math.floor(i / (double) k) * k);
} else {
return (int) (Math.ceil(i / (double) k) * k);
}
}