And more TIMTOWTDI. It's only three lines of code if you don't count the 'use's.

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11159342
use warnings;

my @collapsed = eval <DATA>;
$_->[0] == 0 && $collapsed[-1][0] == 0 ? ($collapsed[-1][1] += $_->[1]
+)
  : $_->[1] == 0 && $collapsed[-1][1] == 0 ? ($collapsed[-1][0] += $_-
+>[0])
    : push @collapsed, $_
  for map eval, <DATA>;
printf "[ %d, %d, %d ],\n", @$_ for @collapsed;

__DATA__
[ -1, 5, 1 ],
[ 0, 5, 1 ],
[ 0, 5, 1 ],
[ 1, 5, 1 ],
[ 3, 4, 1 ],
[ 5, 1, 1 ],
[ 5, 0, 1 ],
[ 5, 0, 1 ],
[ 5, 0, 1 ],
[ 5, 0, 1 ],
[ 5, 0, 1 ],
[ 5, 0, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ 0, -5, 1 ],
[ -23, -64, 0 ],
[ -5, 0, 1 ],
[ -5, 1, 1 ],
[download]

which outputs:

[ -1, 5, 1 ],
[ 0, 10, 1 ],
[ 1, 5, 1 ],
[ 3, 4, 1 ],
[ 5, 1, 1 ],
[ 30, 0, 1 ],
[ 0, -45, 1 ],
[ -23, -64, 0 ],
[ -5, 0, 1 ],
[ -5, 1, 1 ],
[download]