Add a solution to Snapshot Array

Author: soapyigu

Design/SnapshotArray.swift

@@ -0,0 +1,33 @@
+/**
+ * Question Link: https://leetcode.com/problems/snapshot-array/
+ * Primary idea: Use the dictionary to dictionary to hold snapshot id to array data if necessary
+ *
+ * Time Complexity: O(1), Space Complexity: O(n)
+ *
+ */
+
+class SnapshotArray {
+    
+    private var snapshotArrayMap: [Int: [Int: Int]]
+    private var count = 0
+    private var array = [Int: Int]()
+
+    init(_ length: Int) {
+        snapshotArrayMap = [Int: [Int: Int]]()
+    }
+    
+    func set(_ index: Int, _ val: Int) {
+        array[index] = val
+    }
+    
+    func snap() -> Int {
+        snapshotArrayMap[count] = array
+        count += 1
+        
+        return count - 1
+    }
+    
+    func get(_ index: Int, _ snap_id: Int) -> Int {
+        return snapshotArrayMap[snap_id]?[index] ?? 0
+    }
+}