Leetcode1302–层数最深叶子结点的和（深搜/递归）

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
struct TreeNode* dfs(struct TreeNode* root,int deepth,int * sum,int *max_deepth)
{
    if(root == NULL)
        return NULL;
    if(deepth > (*max_deepth))
    {
        (*max_deepth) = deepth;
        (*sum) = 0; //guiling heihei
    }
    struct TreeNode *left,*right;
    left = dfs(root->left,deepth+1,sum,max_deepth);
    right = dfs(root->right,deepth+1,sum,max_deepth); //没有&&&&
    if(left == NULL && right == NULL && deepth == (*max_deepth))
        (*sum) += root->val;
    return root;
}
int deepestLeavesSum(struct TreeNode* root){
    int sum = 0;
    if(root == NULL)
        return 0;
    int max_deepth = 0;
    dfs(root,0,&sum,&max_deepth); //&&&&
    return sum;
}