An equilibrium index of a sequence is an index into the sequence such that the sum of elements at lower indices is equal to the sum of elements at higher indices.



For example, in a sequence   



A


{\displaystyle A}

:

   




A

0


=
−
7


{\displaystyle A_{0}=-7}


   




A

1


=
1


{\displaystyle A_{1}=1}


   




A

2


=
5


{\displaystyle A_{2}=5}


   




A

3


=
2


{\displaystyle A_{3}=2}


   




A

4


=
−
4


{\displaystyle A_{4}=-4}


   




A

5


=
3


{\displaystyle A_{5}=3}


   




A

6


=
0


{\displaystyle A_{6}=0}


3   is an equilibrium index, because:

   




A

0


+

A

1


+

A

2


=

A

4


+

A

5


+

A

6




{\displaystyle A_{0}+A_{1}+A_{2}=A_{4}+A_{5}+A_{6}}


6   is also an equilibrium index, because:

   




A

0


+

A

1


+

A

2


+

A

3


+

A

4


+

A

5


=
0


{\displaystyle A_{0}+A_{1}+A_{2}+A_{3}+A_{4}+A_{5}=0}


(sum of zero elements is zero)

7   is not an equilibrium index, because it is not a valid index of sequence 



A


{\displaystyle A}

.



Task;
Write a function that, given a sequence, returns its equilibrium indices (if any).

Assume that the sequence may be very long.




 
public class Equlibrium {
	public static void main(String[] args) {
		int[] sequence = {-7, 1, 5, 2, -4, 3, 0};
		equlibrium_indices(sequence);
	}
 
	public static void equlibrium_indices(int[] sequence){
		//find total sum
		int totalSum = 0;
		for (int n : sequence) {
			totalSum += n;
		}
		//compare running sum to remaining sum to find equlibrium indices
		int runningSum = 0;
		for (int i = 0; i < sequence.length; i++) {
			int n = sequence[i];
			if (totalSum - runningSum - n == runningSum) {
				System.out.println(i);
			}
			runningSum += n;
		}
	}
}
 