From 06f01d2ef9635bb26d853e9b29ecbdf3f3786956 Mon Sep 17 00:00:00 2001
From: Grzegorz Kucmierz <gkucmierz@gmail.com>
Date: Sat, 23 Nov 2019 23:43:02 +0100
Subject: [PATCH] Cycle Detection: Floyd's The Tortoise and the The Hare

---
 .../index.js                                      | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 cycle-detection-floyds-the-tortoise-and-the-the-hare/index.js

diff --git a/cycle-detection-floyds-the-tortoise-and-the-the-hare/index.js b/cycle-detection-floyds-the-tortoise-and-the-the-hare/index.js
new file mode 100644
index 0000000..a66d72b
--- /dev/null
+++ b/cycle-detection-floyds-the-tortoise-and-the-the-hare/index.js
@@ -0,0 +1,15 @@
+// https://www.codewars.com/kata/cycle-detection-floyds-the-tortoise-and-the-the-hare/javascript
+
+const floyd = function(f, x0) {
+  let x = x0;
+  let i = 0;
+  const map = new WeakMap();
+  
+  while (1) {
+    map[x] = i++;
+    x = f(x);
+    if (x in map) break;
+  }
+  
+  return  [map[x], i - map[x]];
+}