Hi guys.

I'm new to the forum. I was playing with an online Java test from codility about a function that returns the equilibrium index in a sequence of integers (Codility). The problem states:

My solution to this was the following:Equilibrium index of a sequence is an index such that the sum of elements at lower indexes is equal to the sum of elements at higher indexes. For example, in a sequence A:

A[0]=-7 A[1]=1 A[2]=5 A[3]=2 A[4]=-4 A[5]=3 A[6]=0

3 is an equilibrium index, because:

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

(sum of zero elements is zero) 7 is not an equilibrium index, because it is not a valid index of sequence A.

[...]

Assume the sum of zero elements is equal zero. Write a function

int equi(int[] A);

that given a sequence, returns its equilibrium index (any) or -1 if no equilibrium indexes exist. Assume that the sequence may be very long.

int equi ( int[] A ) { int leftSum = 0; int rightSum = 0; for (int iterator= 0; iterator< A.length; iterator++){ rightSum += A[iterator]; } for(int eqIndexCandidate = 0; eqIndexCandidate < A.length; eqIndexCandidate ++){ if (eqIndexCandidate != 0) leftSum += A[eqIndexCandidate - 1]; rightSum -= A[eqIndexCandidate]; if (leftSum == rightSum) return eqIndexCandidate; } return -1; }

However, when I got the results back it seems that I missed one case:

How would you deal with a case that the numbers are too large to fit in an integer ? It seems that Codility would not let me use any packages from the API...