Discussion on: Daily Challenge #265 - Equal Sides

#!/usr/bin/perl
use strict;
use warnings;
use experimental qw{ signatures };
use List::Util qw{ sum };

sub equal_sides ($arr) {
    my ($left, $current, $right) = (0, 0, sum(@$arr[1 .. $#$arr]));
    until ($current > $#$arr || $left == $right) {
        $left += $arr->[$current];
        $right -= $arr->[++$current] // 0;
    }
    return $current > $#$arr ? -1 : $current
}

use Test::More tests => 4;

my @tests = ([1, 2, 3, 4, 3, 2, 1],        3,
             [1, 100, 50, -51, 1, 1],      1,
             [20, 10, 30, 10, 10, 15, 35], 3,
             [-8505, -5130, 1926, -9026], -1);

while (my ($arr, $result) = splice @tests, 0, 2) {
    is equal_sides($arr), $result;
}