public static int chiefHopper(List<Integer> arr){
                ////////////////////
                // Rather than iterating with the different inital energy to find the positive end energy, I should start with +ve end energy
                // and iterate in the last to first to find the minimum positive energy.

                // To calculate this, consider the end energy is 1.
                // The energy before jumping the last building should be :
                // newEnergy = currentEne + delta (currnetEne - height);
                // newEnergy = 2 * currentEne - height;  => We need to have newEnergy >= 0 & need to find the currentEnergy.

                // currentEne = newEnergy + height / 2;

                double newEne = 0;
                double currentEne = 0;

                for(int i = arr.size() - 1; i >= 0; i--){
                        currentEne = Math.ceil( (newEne + arr.get(i)) / 2 );
                        newEne = currentEne;
                }

                return (int)currentEne;
        }