Use 7 as an example, we can obtain some clue about the construction of the array.

7, 1

[1,2,3,4,5,6,7] => [1,1,1,1,1,1]

7,2

[1,7,6,5,4,3,2] => [6,1,1,1,1,1]

7,3

[1,7,2,3,4,5,6] => [6,5,1,1,1,1]

7,4

[1,7,2,6,5,4,3] => [6,5,4,1,1,1]

7,5

[1,7,2,6,3,4,5] => [6,5,4,3,1,1]

7,6

[1,7,2,6,3,5,4] => [6,5,4,3,2,1]

Below is my code implementation

```
class Solution {
public int[] constructArray(int n, int k) {
int[] res = new int[n];
int i, j = 1, m = n, s;
for(i = 0; i < k; i ++) {
if(i % 2 == 0) {
res[i] = j;
j ++;
}
else {
res[i] = m;
m --;
}
}
s = i;
if(s % 2 == 1) {
for(s = i; s < n; s ++) {
res[s] = j;
j ++;
}
}
else {
for(s = i; s < n; s ++) {
res[s] = m;
m --;
}
}
return res;
}
}
```