From 53b1b1d88d6abdc83b5183085525c03fe7ef8aea Mon Sep 17 00:00:00 2001
From: Yi Gu <rio.deliberate@gmail.com>
Date: Sun, 2 Apr 2017 00:05:34 -0700
Subject: [PATCH] Add Solution to Number of Boomerangs

---
 Array/NumberBoomerangs.swift | 35 +++++++++++++++++++++++++++++++++++
 README.md                    |  3 ++-
 2 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 Array/NumberBoomerangs.swift

diff --git a/Array/NumberBoomerangs.swift b/Array/NumberBoomerangs.swift
new file mode 100644
index 00000000..4eaab040
--- /dev/null
+++ b/Array/NumberBoomerangs.swift
@@ -0,0 +1,35 @@
+/**
+ * Question Link: https://leetcode.com/problems/number-of-boomerangs/
+ * Primary idea: traverse the array and compare distance one by one
+ *
+ * Time Complexity: O(n^2), Space Complexity: O(n)
+ *
+ */
+
+ class NumberBoomerangs {
+    func numberOfBoomerangs(_ points: [[Int]]) -> Int {
+        var num = 0
+  
+        for (i, point) in points.enumerated() {
+            var dict = [Int: Int]()
+            for (j, anotherpoint) in points.enumerated() {
+                if i == j {
+                    continue
+                }
+      
+                let distance = (anotherpoint[0] - point[0]) * (anotherpoint[0] - point[0])  + (anotherpoint[1] - point[1]) * (anotherpoint[1] - point[1])
+      
+                if let sameDistancePoints = dict[distance] {
+                    dict[distance] = sameDistancePoints + 1
+                } else {
+                    dict[distance] = 1
+                }
+            }
+    
+            for key in dict.keys {
+                num += dict[key]! * (dict[key]! - 1)
+            }
+        }
+        return num
+    }
+}
\ No newline at end of file
diff --git a/README.md b/README.md
index 75b881c6..86e3e608 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@
 * [Microsoft](#microsoft)
 
 ## Progress
-[Problem Status](#problem-status) shows the latest progress to all 500+ questions. Currently we have 217 completed solutions. Note: questions with &hearts; mark means that you have to **Subscript to premium membership** of LeetCode to unlock them. Thank you for great contributions from [CharleneJiang](https://github.com/CharleneJiang), [ReadmeCritic](https://github.com/ReadmeCritic), [demonkoo](https://github.com/demonkoo), [DaiYue](https://github.com/DaiYue), [Quaggie](https://github.com/Quaggie) and [jindulys](https://github.com/jindulys).
+[Problem Status](#problem-status) shows the latest progress to all 500+ questions. Currently we have 218 completed solutions. Note: questions with &hearts; mark means that you have to **Subscript to premium membership** of LeetCode to unlock them. Thank you for great contributions from [CharleneJiang](https://github.com/CharleneJiang), [ReadmeCritic](https://github.com/ReadmeCritic), [demonkoo](https://github.com/demonkoo), [DaiYue](https://github.com/DaiYue), [Quaggie](https://github.com/Quaggie) and [jindulys](https://github.com/jindulys).
 
 
 ## Array
@@ -35,6 +35,7 @@
 | ----- | -------- | ---------- | ---- | ----- |
 [Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones/)| [Swift](./Array/MaxConsecutiveOnes.swift)| Easy| O(n)| O(1)|
 [Heaters](https://leetcode.com/problems/heaters/)| [Swift](./Array/Heaters.swift)| Easy| O(nlogn)| O(1)|
+[Number of Boomerangs](https://leetcode.com/problems/number-of-boomerangs/)| [Swift](./Array/NumberBoomerangs.swift)| Easy| O(n ^ 2)| O(n)|
 [Island Perimeter](https://leetcode.com/problems/island-perimeter/)| [Swift](./Array/IslandPerimeter.swift)| Easy| O(nm)| O(1)|
 [Majority Element](https://leetcode.com/problems/majority-element/)| [Swift](./Array/MajorityElement.swift)| Easy| O(n)| O(1)|
 [Majority Element II](https://leetcode.com/problems/majority-element-ii/)| [Swift](./Array/MajorityElementII.swift)| Medium| O(n)| O(1)|