solution.py

# You are going to be given an array of integers.
# Your job is to take that array and find an index N where the sum of the integers to the left of N is equal
# to the sum of the integers to the right of N. If there is no index that would make this happen, return -1.

# For example:

# Let's say you are given the array {1,2,3,4,3,2,1}:
# Your function will return the index 3, because at the 3rd position of the array,
# the sum of left side of the index ({1,2,3}) and the sum of the right side of the index ({3,2,1}) both equal 6.

# Let's look at another one.
# You are given the array {1,100,50,-51,1,1}:
# Your function will return the index 1, because at the 1st position of the array,
# the sum of left side of the index ({1}) and the sum of the right side of the index ({50,-51,1,1}) both equal 1.

# Last one:
# You are given the array {20,10,-80,10,10,15,35}
# At index 0 the left side is {}
# The right side is {10,-80,10,10,15,35}
# They both are equal to 0 when added. (Empty arrays are equal to 0 in this problem)
# Index 0 is the place where the left side and right side are equal.

# Note: Please remember that in most programming/scripting languages the index of an array starts at 0.

# Input:
# An integer array of length 0 < arr < 1000. The numbers in the array can be any integer positive or negative.

# Output:
# The lowest index N where the side to the left of N is equal to the side to the right of N.
# If you do not find an index that fits these rules, then you will return -1.

# Note:
# If you are given an array with multiple answers, return the lowest correct index.


def find_even_index(arr):
    for i in range(len(arr)):
        if sum(arr[:i]) == sum(arr[i + 1 :]):
            return i
    return -1