667. Beautiful Arrangement II

class Solution {
    public int[] constructArray(int n, int k) {
        int[] result =new int[n];
        
        int high = n , low = 1;
        int index = 0;
        
        result[index++] = low++;
        
        boolean isHigh = false;
        
        while(k>1){
            result[index++] = high--;
            k--;
            isHigh = true;
            if(k>1){
                result[index++] = low++;
                k--;
                isHigh = false;
            }
        }
        
        //increasing or decreasing
        while(index<n){
            if(isHigh){
                result[index++] = high--;
            }
            else{
                result[index++] = low++;
            }
        }
        
        return result;
    }
}