fetch 1~k + 1 to satisfy the requirement(like 1 , k + 1, 2, k, 3, k - 1,.....)

'''

class Solution {

public:

vector<int> constructArray(int n, int k) {

int x = 1, y = k + 1;

std::vector<int> v;

while(x < y)

{

v.push_back(x);

v.push_back(y);

x++;

y--;

}

if(x == y)

v.push_back(x);

for(int i = k + 2; i <= n; i++)

v.push_back(i);

return v;

}

};