From 15e94c02862790d83a38495d8fb6a5d36a7e6f97 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Mon, 7 Dec 2020 22:46:36 -0800
Subject: [PATCH] Add 'find_indices'

---
 src/advent/util.cr | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/advent/util.cr b/src/advent/util.cr
index 52b8c3b..1bcce64 100644
--- a/src/advent/util.cr
+++ b/src/advent/util.cr
@@ -33,6 +33,14 @@ class Array(T)
       puts
     end
   end
+
+  def find_indices
+    into = [] of T
+    each_with_index do |v, i|
+      into << i if yield v
+    end
+    into
+  end
 end
 
 struct Tuple(*T)