From 392152e581a9176e9013e786b2d8f94e0ebb3b57 Mon Sep 17 00:00:00 2001
From: Tyler Wardhaugh <tyler.wardhaugh@gmail.com>
Date: Tue, 20 Oct 2020 12:36:44 -0700
Subject: Ch83 (Lua): Task 2

---
 challenge-083/tyler-wardhaugh/lua/ch-2.lua | 34 ++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100755 challenge-083/tyler-wardhaugh/lua/ch-2.lua

(limited to 'challenge-083/tyler-wardhaugh/lua/ch-2.lua')

diff --git a/challenge-083/tyler-wardhaugh/lua/ch-2.lua b/challenge-083/tyler-wardhaugh/lua/ch-2.lua
new file mode 100755
index 0000000000..bf900a864e
--- /dev/null
+++ b/challenge-083/tyler-wardhaugh/lua/ch-2.lua
@@ -0,0 +1,34 @@
+#!/usr/bin/env lua
+
+local t2 = {}
+
+function t2.flip_array(coll)
+  local min_flips = math.maxinteger
+  local min_sum = math.maxinteger
+  local max_bits = 2^#coll - 1
+
+  local cur_num, cur_sum, is_neg
+  for bits = 1, max_bits do
+    cur_num, cur_sum, is_neg = 0, 0, 0
+    for i, v in ipairs(coll) do
+      is_neg = bits & 2^(i-1) == 0
+      cur_num = cur_num + (is_neg and 1 or 0)
+      cur_sum = cur_sum + v * (is_neg and -1 or 1)
+    end
+
+    if 0 <= cur_sum and cur_sum <= min_sum then
+        min_flips = math.min(cur_num, min_flips)
+        min_sum = cur_sum
+    end
+  end
+
+  return min_flips
+end
+
+
+function t2.run(args)
+  local minimum = t2.flip_array(args)
+  print(minimum)
+end
+
+return t2
-- 
cgit