Merge pull request #3747 from drxlx/2013-detect-squares

Create 2013-detect-squares.swift

swift/2013-detect-squares.swift

@@ -0,0 +1,35 @@
+
+class DetectSquares {
+
+    var pts = [[Int]]()
+    var ptsCount = [[Int]: Int]()
+
+    init() {
+
+    }
+
+    func add(_ point: [Int]) {
+        ptsCount[point, default: 0] += 1
+        pts.append(point)
+    }
+
+    func count(_ point: [Int]) -> Int {
+        var res = 0
+        var x = point[0], y = point[1]
+        for val in pts {
+            let px = val[0], py = val[1]
+            if abs(py - y) != abs(px - x) || x == px || y == py {
+                continue
+            }
+            res += ptsCount[[x, py], default: 0] * ptsCount[[px, y], default: 0]
+        }
+        return res
+    }
+}
+
+/**
+ * Your DetectSquares object will be instantiated and called as such:
+ * let obj = DetectSquares()
+ * obj.add(point)
+ * let ret_2: Int = obj.count(point)
+ */