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.
- findEvenIndex([1,2,3,4,3,2,1] should return 3.
- findEvenIndex([1,100,50,-51,1,1]) should return 1.
- findEvenIndex([1,2,3,4,5,6]) should return -1.
- findEvenIndex([20,10,30,10,10,15,35]) should return 3.
function findEvenIndex(arr) {
//Code goes here!
}