Optimize code style by Swifter way

sarojtiwari · Jan 24, 2017 · c245e0f · c245e0f
1 parent 79fa129
commit c245e0f
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Showing 5 changed files with 26 additions and 43 deletions.
diff --git a/Array/SetMatrixZeroes.swift b/Array/SetMatrixZeroes.swift
@@ -11,18 +11,14 @@ class SetMatrixZeroes {
         var rowHasZero = false, colHasZero = false
         let m = matrix.count, n = matrix[0].count
 
-        for i in 0 ..< m {
-            if matrix[i][0] == 0 {
-                colHasZero = true
-                break
-            }
+        for i in 0 ..< m where matrix[i][0] == 0 {
+            colHasZero = true
+            break
         }
 
-        for i in 0 ..< n {
-            if matrix[0][i] == 0 {
-                rowHasZero = true
-                break
-            }
+        for i in 0 ..< n where matrix[0][i] == 0 {
+            rowHasZero = true
+            break
         }
 
         for i in 1 ..< m {

diff --git a/DFS/FactorCombinations.swift b/DFS/FactorCombinations.swift
@@ -28,12 +28,10 @@ class FactorCombinations {
             return
         }
 
-        for i in start ... n {
-            if n % i == 0 {
-                path.append(i)
-                dfs(&res, &path, n / i, i)
-                path.removeLast()
-            }
+        for i in start ... n where n % i == 0 {
+            path.append(i)
+            dfs(&res, &path, n / i, i)
+            path.removeLast()
         }
     }
 }
diff --git a/DFS/Permutations.swift b/DFS/Permutations.swift
@@ -7,34 +7,27 @@
  */
 
 class Permutations {
-    func permute(nums: [Int]) -> [[Int]] {
+    func permute(_ nums: [Int]) -> [[Int]] {
         var res = [[Int]]()
         var path = [Int]()
-        var visited = [Bool](count: nums.count, repeatedValue: false)
+        var isVisited = [Bool](repeating: false, count: nums.count)
 
-        let nums = nums.sort({$0 < $1})
-
-        _dfs(&res, &path, nums, &visited)
+        dfs(&res, &path, &isVisited, nums)
 
         return res
     }
 
-    private func _dfs(inout res: [[Int]], inout _ path: [Int], _ nums: [Int], inout _ visited: [Bool]) {
-        // termination case
-        if path.count == nums.count {
-            res.append(Array(path))
+    private func dfs(_ res: inout [[Int]], _ path: inout [Int], _ isVisited: inout [Bool], _ nums: [Int]) {
+        guard path.count != nums.count else {
+            res.append(path)
             return
         }
 
-        for i in 0 ..< nums.count {
-            guard !visited[i] else {
-                continue
-            }
-
-            path.append(nums[i])
-            visited[i] = true
-            _dfs(&res, &path, nums, &visited)
-            visited[i] = false
+        for (i, num) in nums.enumerated() where !isVisited[i] {
+            path.append(num)
+            isVisited[i] = true
+            dfs(&res, &path, &isVisited, nums)
+            isVisited[i] = false
             path.removeLast()
         }
     }

diff --git a/DP/BestTimeBuySellStockII.swift b/DP/BestTimeBuySellStockII.swift
@@ -13,10 +13,8 @@
             return max
         }
 
-        for i in 1 ..< prices.count {
-            if prices[i] > prices[i - 1] {
-                max += prices[i] - prices[i - 1]
-            }
+        for i in 1 ..< prices.count where prices[i] > prices[i - 1] {
+            max += prices[i] - prices[i - 1]
         }
 
         return max

diff --git a/Tree/ConstructBinaryTreeInorderPostorder.swift b/Tree/ConstructBinaryTreeInorderPostorder.swift
@@ -34,11 +34,9 @@ class ConstructBinaryTreeInorderPostorder {
         let root = TreeNode(postorder[postEnd])
 
         var mid = 0
-        for i in inStart ... inEnd {
-            if inorder[i] == root.val {
-                mid = i
-                break
-            }
+        for i in inStart ... inEnd where inorder[i] == root.val {
+            mid = i
+            break
         }
 
         root.left = _buildHelper(inorder, inStart, mid - 1, postorder, postStart, mid - 1 - inStart + postStart)