目录

一、题目

二、代码

---

一、题目

二、代码

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    static int MAX;
    void MAX_ProOrder(TreeNode* root)
    {
        if(root==nullptr)//结束条件
        {
            return;
        }
        MAX = MAX>root->val?MAX:root->val;
        MAX_ProOrder(root->left);
        MAX_ProOrder(root->right);

    }

    void ProOrder(TreeNode* root,vector<int>&a)
    {
        if(root==nullptr)
        {
            return;
        }

        a[root->val]=1;
        ProOrder(root->left,a);
        ProOrder(root->right,a);
    }
    int numColor(TreeNode* root) {
       MAX_ProOrder(root);
       vector<int>a(MAX+1,0);
        ProOrder(root,a);

        int Count=0;
        for(int i=0;i<=MAX;i++)
        {
            if(a[i]!=0)
            {
              Count++;
            }
        }
        return Count;

    }
};
int Solution::MAX=0;