[Swift]LeetCode100. 相同的树 | Same Tree

★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
➤微信公众号：山青咏芝（shanqingyongzhi）
➤博客园地址：山青咏芝（https://www.cnblogs.com/strengthen/）
➤GitHub地址：https://github.com/strengthen/LeetCode
➤原文地址：https://www.cnblogs.com/strengthen/p/9697990.html 
➤如果链接不是山青咏芝的博客园地址，则可能是爬取作者的文章。
➤原文已修改更新！强烈建议点击原文地址阅读！支持作者！支持原创！
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

Example 1:

Input:     1         1
          /        / 
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1
          /           
         2             2

        [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1
          /        / 
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false

---

给定两个二叉树，编写一个函数来检验它们是否相同。

如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的。

示例 1:

输入:       1         1
          /        / 
         2   3     2   3

        [1,2,3],   [1,2,3]

输出: true

示例 2:

输入:      1          1
          /           
         2             2

        [1,2],     [1,null,2]

输出: false

示例 3:

输入:       1         1
          /        / 
         2   1     1   2

        [1,2,1],   [1,1,2]

输出: false

---

8ms

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public var val: Int
 *     public var left: TreeNode?
 *     public var right: TreeNode?
 *     public init(_ val: Int) {
 *         self.val = val
 *         self.left = nil
 *         self.right = nil
 *     }
 * }
 */
class Solution {
    func isSameTree(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
        return (p == nil && q == nil) || (p?.val == q?.val) && isSameTree(p?.right, q?.right) && isSameTree(p?.left, q?.left)
    }
}

---

12ms

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public var val: Int
 *     public var left: TreeNode?
 *     public var right: TreeNode?
 *     public init(_ val: Int) {
 *         self.val = val
 *         self.left = nil
 *         self.right = nil
 *     }
 * }
 */
class Solution {
    func isSameTree(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
        if p?.val != q?.val {
            return false
        }
        if p?.left == nil && q?.left == nil && p?.right == nil && q?.right == nil {
            return true
        }else{
            return isSameTree(p?.left, q?.left) && isSameTree(p?.right, q?.right)
        }
    }
}

---

12ms

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public var val: Int
 *     public var left: TreeNode?
 *     public var right: TreeNode?
 *     public init(_ val: Int) {
 *         self.val = val
 *         self.left = nil
 *         self.right = nil
 *     }
 * }
 */
class Solution {
    func isSameTree(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
        var queue: [(TreeNode?,TreeNode?)] = [(p,q)]
        while !queue.isEmpty {
            let (a,b) = queue.removeFirst()
            if !isEquaNode(a,b) {
                return false
            }
            if let leftA = a?.left, let leftB = b?.left {
                queue.append((leftA, leftB))
            }
            if let rightA = a?.right, let rightB = b?.right {
                queue.append((rightA, rightB))
            }
        }
        return true
    }
    
    func isEquaNode(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
        if p == nil && q == nil { return true }
        if p == nil && q != nil { return false }
        if p != nil && q == nil { return false }
        return p!.val == q!.val &&
        p!.left?.val == q!.left?.val &&
        p!.right?.val == q!.right?.val
    }
}

---

16ms

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public var val: Int
 *     public var left: TreeNode?
 *     public var right: TreeNode?
 *     public init(_ val: Int) {
 *         self.val = val
 *         self.left = nil
 *         self.right = nil
 *     }
 * }
 */
class Solution {
    func isSameTree(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
        
       if p?.val != q?.val {
            return false
        }
        if p?.left != nil{
            if p?.left?.val == q?.left?.val{
                if !isSameTree(p?.left, q?.left){
                    return false
                }
            }else{
                return false
            }
        }else if q?.left != nil{
            return false
        }
        if p?.right != nil {
            if p?.right?.val == q?.right?.val{
                if !isSameTree(p?.right, q?.right){
                    return false
                }
            }else{
                return false
            }
        }else if q?.right != nil{
            return false
        }
        return true;
    }
}

---

24ms

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public var val: Int
 *     public var left: TreeNode?
 *     public var right: TreeNode?
 *     public init(_ val: Int) {
 *         self.val = val
 *         self.left = nil
 *         self.right = nil
 *     }
 * }
 */
class Solution {
    func isSameTree(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
        //递归
        if let p = p, let q = q 
        {
            return p.val == q.val && isSameTree(p.left,q.left)
            && isSameTree(p.right,q.right)        
        }
        else
        {
            return p == nil && q == nil
        }
    }
}