public void sort(int[] nums){ int len = nums.length; int first = 0; int last = len; int mid = 0; while(mid<last){ if(nums[mid]<0){  if (mid==first){
                mid++;
                first++; continue;
            } int i = mid; int tmp = nums[mid]; while(i>first){
               nums[i]= nums[i-1];
               i--;
            }
            nums[first] = tmp;
            first++;
        } else if(nums[mid]>0){ int i = mid; int tmp = nums[mid]; while(i<len-1){
                nums[i] = nums[i+1];
                i++;
            }
            nums[len-1]=tmp;
            last--;
        } else{
            mid++;
        }
    }
}