[force buckle] single valued binary tree

965. Single valued binary trees - Power button （LeetCode）

subject ：

If each node of the binary tree has the same value , Then the binary tree is Single value Binary tree .

Only when the given tree is a single valued binary tree , To return to  true; Otherwise return to  false.

Ideas ：

If it is empty, return true

If root Left of / When the right child is not empty , Compare left / Right child and root The value of the node , Unequal return false

Code ：

bool isUnivalTree(struct TreeNode* root){
    if(root == NULL)
    {
        return true;
    }
    if(root->left)
    {
        if(root->left->val != root->val)
        {
            return false;
        }
    }
    if(root->right)
    {
        if(root->right->val != root->val)
        {
            return false;
        }
    }
    bool ret1 = isUnivalTree(root->left);
    bool ret2 = isUnivalTree(root->right);
    
    return ret1&&ret2;

}