From 37b05bf1735ef9826b5db8d32835077799ba21ce Mon Sep 17 00:00:00 2001
From: Grzegorz Kucmierz <gkucmierz@gmail.com>
Date: Tue, 19 Nov 2019 15:04:52 +0100
Subject: [PATCH] Sum of Pairs

---
 sum-of-pairs/index.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 sum-of-pairs/index.js

diff --git a/sum-of-pairs/index.js b/sum-of-pairs/index.js
new file mode 100644
index 0000000..5dc4d51
--- /dev/null
+++ b/sum-of-pairs/index.js
@@ -0,0 +1,12 @@
+// https://www.codewars.com/kata/sum-of-pairs/train/javascript
+
+const sum_pairs = (arr, sum) => {
+  const map = new WeakMap();
+  for (let i = 0; i < arr.length; ++i) {
+    if (map[arr[i]]) {
+      return [sum - arr[i], arr[i]];
+    }
+    map[sum - arr[i]] = true;
+  }
+  return [];
+};