From 019f20a2c714ed05f17a7e174ba9da0cc8b820e9 Mon Sep 17 00:00:00 2001
From: cediackermann <ackermanncedi@gmail.com>
Date: Mon, 8 Jun 2026 10:39:44 +0200
Subject: [PATCH] make purely pure functions

---
 Sources/LeetCode/LeetCode.swift | 66 ++++++++++++++-------------------
 Sources/LeetCode/main.swift     | 10 ++---
 2 files changed, 31 insertions(+), 45 deletions(-)

diff --git a/Sources/LeetCode/LeetCode.swift b/Sources/LeetCode/LeetCode.swift
index 14e7a36..c4667cb 100644
--- a/Sources/LeetCode/LeetCode.swift
+++ b/Sources/LeetCode/LeetCode.swift
@@ -1,50 +1,38 @@
 import Foundation
 
-//
-//  LeetCode.swift
-//  m323
-//
-//  Created by cediackermann on 18.05.2026.
-//
-
-class LeetCode {
-    func hammingWeight(_ n: Int) -> Int {
-        return n == 0 ? 0 : (n & 1) + hammingWeight(n >> 1)
+enum LeetCode {
+    static func hammingWeight(_ n: Int) -> Int {
+        n == 0 ? 0 : (n & 1) + hammingWeight(n >> 1)
     }
 
-    func singleNumber(_ nums: [Int]) -> Int {
-        var result = 0
-        for num in nums {
-            result ^= num
+    static func singleNumber(_ nums: [Int]) -> Int {
+        nums.reduce(0, ^)
+    }
+
+    static func containsDuplicate(_ nums: [Int]) -> Bool {
+        nums.count != Set(nums).count
+    }
+
+    static func sortedSquares(_ nums: [Int]) -> [Int] {
+        nums.map { $0 * $0 }.sorted()
+    }
+
+    static func productExceptSelf(_ nums: [Int]) -> [Int] {
+        let n = nums.count
+        var result = [Int](repeating: 1, count: n)
+
+        var prefix = 1
+        for i in 0..<n {
+            result[i] = prefix
+            prefix *= nums[i]
         }
-        return result
-    }
 
-    func containsDuplicate(_ nums: [Int]) -> Bool {
-        return nums.count != Set(nums).count
-    }
-
-    func sortedSquares(_ nums: [Int]) -> [Int] {
-        return nums.map { $0 * $0 }.sorted()
-    }
-
-    func productExceptSelf(_ nums: [Int]) -> [Int] {
-        var result = [Int](repeating: 1, count: nums.count)
-        var prefix = [Int](repeating: 1, count: nums.count)
-        var suffix = [Int](repeating: 1, count: nums.count)
-        var runningProduct = 1
-        for i in 0..<nums.count {
-            prefix[i] = runningProduct
-            runningProduct *= nums[i]
-        }
-        runningProduct = 1
-        for i in stride(from: nums.count - 1, through: 0, by: -1) {
-            suffix[i] = runningProduct
-            runningProduct *= nums[i]
-            result[i] = prefix[i] * suffix[i]
+        var suffix = 1
+        for i in stride(from: n - 1, through: 0, by: -1) {
+            result[i] *= suffix
+            suffix *= nums[i]
         }
 
         return result
     }
-
 }
diff --git a/Sources/LeetCode/main.swift b/Sources/LeetCode/main.swift
index eae89ad..adb7e23 100644
--- a/Sources/LeetCode/main.swift
+++ b/Sources/LeetCode/main.swift
@@ -5,9 +5,7 @@
 //  Created by cediackermann on 18.05.2026.
 //
 
-let code = LeetCode()
-
-// print(code.hammingWeight(2_147_483_645))
-// print(code.singleNumber([4, 1, 2, 1, 2]))
-// print(code.containsDuplicate([1, 2, 3, 4]))
-// print(code.productExceptSelf([-1, 1, 0, -3, 3]))
+// print(LeetCode.hammingWeight(2_147_483_645))
+// print(LeetCode.singleNumber([4, 1, 2, 1, 2]))
+// print(LeetCode.containsDuplicate([1, 2, 3, 4]))
+// print(LeetCode.productExceptSelf([-1, 1, 0, -3, 3]))