Leetcode 513. Find Bottom Left Tree Value | dfs

https://leetcode.com/problems/find-bottom-left-tree-value/description/

就一个点

class Solution {
public:
    
    void dfs(TreeNode* root, int cur_dep, int &dep, int &v) {
        if ( !root ) return;
        if (root->left == NULL && root->right == NULL) {
            if (cur_dep > dep) {
                dep = cur_dep;
                v = root->val;
            }
            return ;
        }
        
        dfs(root->left, cur_dep+1, dep, v);
        dfs(root->right, cur_dep+1, dep, v);
    }
    
    int findBottomLeftValue(TreeNode* root) {
        int dep = -1, v = 0;
        dfs(root, 0, dep, v);
        return v;
    }
};