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A zero-indexed array A consisting of N integers is given. An equilibrium index of this array is any integer P such that 0 P N and the sum of elements of lower indices is equal to the sum of elements of higher indices, i.e.

A[0] + A[1] + ... + A[P1] = A[P+1] + ... + A[N2] + A[N1].

Sum of zero elements is assumed to be equal to 0. This can happen if P = 0 or if P = N1.

For example, consider the following array A consisting of N = 7 elements:

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

P = 3 is an equilibrium index of this array, because:

A[0] + A[1] + A[2] = A[4] + A[5] + A[6]

P = 6 is also an equilibrium index, because:

A[0] + A[1] + A[2] + A[3] + A[4] + A[5] = 0

and there are no elements with indices greater than 6.

P = 7 is not an equilibrium index, because it does not fulfill the condition 0 P N.

Write a function

Private Function equi ( A As Integer() ) as Integer

that, given a zero-indexed array A consisting of N integers, returns any of its equilibrium indices. The function should return 1 if no equilibrium index exists.

Assume that:

N is an integer within the range [0..10,000,000];
each element of array A is an integer within the range [2,147,483,648..2,147,483,647].

For example, given array A such that

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

the function may return 3 or 6, as explained above.

Complexity:

expected worst-case time complexity is O(N);
expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified.


My eyes glossed over trying to read this....
I suppose my first problem is I don't know what an equilibrium indices is.

I guess I suck at programming. Or probably reading comprehension.

I tried this

try
return 6
catch
return 3
end try

I figured it should be right at least half the time, but it gave me a zero