leetcode代码分类汇总之-树

leetcode中关于树的题目汇总，这部分题目比较多：

Balanced Binary Tree

[cpp] class Solution {
public:
    int subBal(TreeNode* root){
        if(root==NULL)
            return 0;
        int left = subBal(root->left);
        int right = subBal(root->right);
        if(left<0||right<0||abs(left-right)>1) return -1;
        return max(left,right)+1;
    }
    bool isBalanced(TreeNode *root) {
        return subBal(root)>=0;
    }
};

class Solution {
public:
    int subBal(TreeNode* root){
        if(root==NULL)
            return 0;
        int left = subBal(root->left);
        int right = subBal(root->right);
        if(left<0||right<0||abs(left-right)>1) return -1;
        return max(left,right)+1;
    }
    bool isBalanced(TreeNode *root) {
        return subBal(root)>=0;
    }
};
Binary Tree Inorder Traversal

这个给出两种实现，第一种是网上的，第二种是用我说的比较通用的转化方法做的：

[cpp] class Solution {
public:
    vector<int> inorderTraversal(TreeNode *root) {
        vector<int> ans;
        if(root==NULL) return ans;
        stack<TreeNode*> s;
        while(root!=NULL || !s.empty())
        {
            while(root!=NULL)
            {
                s.push(root);
                root = root->left;
            }
            if(!s.empty())
            {
                root = s.top();
                s.pop();
                ans.push_back(root->val);
                root = root->right;
            }
        }
        return ans;
    }
};

class Solution {
public:
    vector<int> inorderTraversal(TreeNode *root) {
        vector<int> ans;
        if(root==NULL) return ans;
        stack<TreeNode*> s;
        while(root!=NULL || !s.empty())
        {
            while(root!=NULL)
            {
                s.push(root);
                root = root->left;
            }
            if(!s.empty())
            {
                root = s.top();
                s.pop();
                ans.push_back(root->val);
                root = root->right;
            }
        }
        return ans;
    }
};
[cpp] class Solution {
public:
    struct Node{
        TreeNode* node_;
        bool sign;
        Node(TreeNode* n){node_=n;sign=false;}
    };
    vector<int> inorderTraversal(TreeNode *root) {
        stack<Node> stk;
        stk.push(Node(root));
        vector<int> result;
        if(!root) return result;
        while(!stk.empty()){
            Node tmp = stk.top();
            stk.top().sign = true;
            if(tmp.sign){
                result.push_back(tmp.node_->val);
                stk.pop();
                if(tmp.node_->right)
                  stk.push(Node(tmp.node_->right));
            }else if(tmp.node_->left)
              stk.push(Node(tmp.node_->left));
        }
        return result;
    }
};

class Solution {
public:
    struct Node{
        TreeNode* node_;
        bool sign;
        Node(Tree

补充：软件开发 , C++ ,