[sonjh1217] WEEK 02 solutions

product-of-array-except-self/sonjh1217.swift

@@ -0,0 +1,24 @@
+class Solution {
+    func productExceptSelf(_ nums: [Int]) -> [Int] {
+        var answer = [Int]()
+        var product:Int = 1
+        for i in (0..<nums.count) {
+            if i > 0 {
+                product *= nums[i-1]
+            }
+            answer.append(product)
+        }
+
+        product = 1
+        for i in (1..<nums.count) {
+            product *= nums[nums.count-i]
+            answer[nums.count-1-i] *= product
+        }
+
+        return answer
+
+        //시간 복잡도 O(n)
+        //공간 복잡도 O(n)
+    }
+}
+

valid-anagram/sonjh1217.swift

@@ -0,0 +1,22 @@
+class Solution {
+    func isAnagram(_ s: String, _ t: String) -> Bool {
+        var count = [Character:Int]()
+        for char in s {
+            count[char, default: 0] += 1
+        }
+
+        for char in t {
+            count[char, default: 0] -= 1
+
+            if count[char]! < 0 {
+                return false
+            }
+        }
+
+        return count.values.allSatisfy {$0 == 0}
+
+        //시간 복잡도 O(n)
+        //공간 복잡도 O(n)
+    }
+}
+