public static void main(String[] args) {

int[] nums = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30};

int target = 12;

System.out.println(forRange(nums,target));

}

public static int forRange(int[] nums, int target){

int start = 0;

int end = 1;

while(nums[end]<target){

int newstart = end+1;

end = end + (end-start+1)*2;

start = newstart;

}

return binarysearch(nums,target,start,end);

}

public static int binarysearch(int[] nums,int target, int start ,int end){

while(start<=end){

int mid = (start+end)/2;

if(target<nums[mid]){

end = mid-1;

}else if(target>nums[mid]){

start = mid+1;

}else{

return mid;

}

}

return -1;

}