diff --git "a/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md" "b/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md"
index 1a92d42f91..8d6d2502a0 100644
--- "a/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md"
+++ "b/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md"
@@ -273,32 +273,29 @@ function levelOrder(root: TreeNode | null): number[][] {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func levelOrder(_ root: TreeNode?) -> [[Int]] {
-    var res = [[Int]]()
-    guard let root = root else {
-        return res
-    }
-    var queue = [TreeNode]()
-    queue.append(root)
+    var result = [[Int]]()
+    guard let root = root else { return result }
+    // 表示一层
+    var queue = [root]
     while !queue.isEmpty {
-        let size = queue.count
-        var sub = [Int]()
-        for _ in 0 ..< size {
+        let count = queue.count
+        var subarray = [Int]()
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            sub.append(node.val)
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
-            }
+            subarray.append(node.val)
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node) }
         }
-        res.append(sub)
+        result.append(subarray)
     }
-    return res
+
+    return result
 }
 ```
 
@@ -505,30 +502,29 @@ function levelOrderBottom(root: TreeNode | null): number[][] {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func levelOrderBottom(_ root: TreeNode?) -> [[Int]] {
-    var res =  [[Int]]()
-    guard let root = root else {
-        return res
-    }
-    var queue:  [TreeNode] = [root]
+    // 表示一层
+    var queue = [TreeNode]()
+    if let node = root { queue.append(node) }
+    var result = [[Int]]()
     while !queue.isEmpty {
-        var sub = [Int]()
-        for _ in 0 ..< queue.count {
+        let count = queue.count
+        var subarray = [Int]()
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            sub.append(node.val)
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
-            }
+            subarray.append(node.val)
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node)}
         }
-        res.insert(sub, at: 0)
+        result.append(subarray)
     }
-    return res
+
+    return result.reversed()
 }
 ```
 
@@ -729,37 +725,31 @@ function rightSideView(root: TreeNode | null): number[] {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func rightSideView(_ root: TreeNode?) -> [Int] {
-    var res = [Int]()
-    guard let root = root else {
-        return res
-    }
+    // 表示一层
     var queue = [TreeNode]()
-    queue.append(root)
+    if let node = root { queue.append(node) }
+    var result = [Int]()
     while !queue.isEmpty {
-        let size = queue.count
-        for i in 0 ..< size {
+        let count = queue.count
+        for i in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            if i == size - 1 {
-                // 保存 每层最后一个元素
-                res.append(node.val)
-            }
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
-            }
+            if i == count - 1 { result.append(node.val) }
+
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node) }
         }
     }
-    return res
+
+    return result
 }
 ```
 
-
 # 637.二叉树的层平均值
 
 [力扣题目链接](https://leetcode-cn.com/problems/average-of-levels-in-binary-tree/)
@@ -965,32 +955,30 @@ function averageOfLevels(root: TreeNode | null): number[] {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func averageOfLevels(_ root: TreeNode?) -> [Double] {
-    var res = [Double]()
-    guard let root = root else {
-        return res
-    }
+    // 表示一层
     var queue = [TreeNode]()
-    queue.append(root)
+    if let node = root { queue.append(node) }
+    var result = [Double]()
     while !queue.isEmpty {
-        let size = queue.count
+        let count = queue.count
         var sum = 0
-        for _ in 0 ..< size {
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
             sum += node.val
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
-            }
+
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node) }
         }
-        res.append(Double(sum) / Double(size))
+        result.append(Double(sum) / Double(count))
     }
-    return res
+
+    return result
 }
 ```
 
@@ -1212,29 +1200,28 @@ function levelOrder(root: Node | null): number[][] {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func levelOrder(_ root: Node?) -> [[Int]] {
-    var res = [[Int]]()
-    guard let root = root else {
-        return res
-    }
+    // 表示一层
     var queue = [Node]()
-    queue.append(root)
+    if let node = root { queue.append(node) }
+    var result = [[Int]]()
     while !queue.isEmpty {
-        let size = queue.count
-        var sub = [Int]()
-        for _ in 0 ..< size {
+        let count = queue.count
+        var subarray = [Int]()
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            sub.append(node.val)
-            for childNode in node.children {
-                queue.append(childNode)
-            }
+            subarray.append(node.val)
+            // 下一层
+            for node in node.children { queue.append(node) }
         }
-        res.append(sub)
+        result.append(subarray)
     }
-    return res
+
+    return result
 }
 ```
 
@@ -1419,34 +1406,30 @@ function largestValues(root: TreeNode | null): number[] {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func largestValues(_ root: TreeNode?) -> [Int] {
-    var res = [Int]()
-    guard let root = root else {
-        return res
-    }
+    // 表示一层
     var queue = [TreeNode]()
-    queue.append(root)
+    if let node = root { queue.append(node) }
+    var result = [Int]()
     while !queue.isEmpty {
-        let size = queue.count
-        var max: Int = Int.min
-        for _ in 0 ..< size {
+        let count = queue.count
+        var max = queue[0].val
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            if node.val > max {
-                max = node.val
-            }
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
-            }
+            if node.val > max { max = node.val }
+
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node) }
         }
-        res.append(max)
+        result.append(max)
     }
-    return res
+
+    return result
 }
 ```
 
@@ -1456,7 +1439,7 @@ func largestValues(_ root: TreeNode?) -> [Int] {
 
 给定一个完美二叉树，其所有叶子节点都在同一层，每个父节点都有两个子节点。二叉树定义如下：
 
-```
+```cpp
 struct Node {
   int val;
   Node *left;
@@ -1677,33 +1660,34 @@ func connect(root *Node) *Node {
 }
 ```
 
-Swift:
+Swift：
+
 ```swift
 func connect(_ root: Node?) -> Node? {
-    guard let root = root else {
-        return nil
-    }
+    // 表示一层
     var queue = [Node]()
-    queue.append(root)
+    if let node = root { queue.append(node) }
     while !queue.isEmpty {
-        let size = queue.count
-        var preNode: Node?
-        for i in 0 ..< size {
-            let node = queue.removeFirst()
+        let count = queue.count
+        var current, previous: Node!
+        for i in 0 ..< count {
+            // 当前层
             if i == 0 {
-                preNode = node
+                previous = queue.removeFirst()
+                current = previous
             } else {
-                preNode?.next = node
-                preNode = node
-            }
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
+                current = queue.removeFirst()
+                previous.next = current
+                previous = current
             }
+
+            // 下一层
+            if let node = current.left { queue.append(node) }
+            if let node = current.right { queue.append(node) }
         }
+        previous.next = nil
     }
+
     return root
 }
 ```
@@ -1927,34 +1911,34 @@ func connect(root *Node) *Node {
     return root
 }
 ```
-
 Swift：
+
 ```swift
 func connect(_ root: Node?) -> Node? {
-    guard let root = root else {
-        return nil
-    }
+    // 表示一层
     var queue = [Node]()
-    queue.append(root)
+    if let node = root { queue.append(node) }
     while !queue.isEmpty {
-        let size = queue.count
-        var preNode: Node?
-        for i in 0 ..< size {
-            let node = queue.removeFirst()
+        let count = queue.count
+        var current, previous: Node!
+        for i in 0 ..< count {
+            // 当前层
             if i == 0 {
-                preNode = node
+                previous = queue.removeFirst()
+                current = previous
             } else {
-                preNode?.next = node
-                preNode = node
-            }
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
+                current = queue.removeFirst()
+                previous.next = current
+                previous = current
             }
+
+            // 下一层
+            if let node = current.left { queue.append(node) }
+            if let node = current.right { queue.append(node) }
         }
+        previous.next = nil
     }
+
     return root
 }
 ```
@@ -2151,29 +2135,28 @@ function maxDepth(root: TreeNode | null): number {
 };
 ```
 
-Swift:
+Swift：
 
 ```swift
 func maxDepth(_ root: TreeNode?) -> Int {
-    guard let root = root else {
-        return 0
-    }
+    guard root != nil else { return 0 }
+    var depth = 0
     var queue = [TreeNode]()
-    queue.append(root)
-    var res: Int = 0
+    queue.append(root!)
     while !queue.isEmpty {
-        for _ in 0 ..< queue.count {
+        let count = queue.count
+        depth += 1
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
-            }
+
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node) }
         }
-        res += 1
     }
-    return res
+
+    return depth
 }
 ```
 
@@ -2374,28 +2357,25 @@ Swift：
 
 ```swift
 func minDepth(_ root: TreeNode?) -> Int {
-    guard let root = root else {
-        return 0
-    }
-    var res = 0
-    var queue = [TreeNode]()
-    queue.append(root)
+    guard root != nil else { return 0 }
+    var depth = 0
+    var queue = [root!]
     while !queue.isEmpty {
-        res += 1
-        for _ in 0 ..< queue.count {
+        let count = queue.count
+        depth += 1
+        for _ in 0 ..< count {
+            // 当前层
             let node = queue.removeFirst()
-            if node.left == nil && node.right == nil {
-                return res
-            }
-            if let left = node.left {
-                queue.append(left)
-            }
-            if let right = node.right {
-                queue.append(right)
+            if node.left == nil, node.right == nil { // 遇到叶子结点则返回
+                return depth
             }
+
+            // 下一层
+            if let node = node.left { queue.append(node) }
+            if let node = node.right { queue.append(node) }
         }
     }
-    return res
+    return depth
 }
 ```