题解 | #二叉树根节点到叶子节点的所有路径和#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */

class Solution {
public:
    /**
     * 
     * @param root TreeNode类 
     * @return int整型
     */
    int sum = 0;
    void dfs(TreeNode* root,string num){
        if(root == NULL)
            return;
        num += to_string(root->val);
        if(root->left == NULL && root->right == NULL){
            sum += atoi(num.c_str());
            return;
        }
//         if(root->right == NULL){
//             sum += atoi(num.c_str());
//             dfs(root->left,num);
//         }
//         else if(root->left == NULL){
//             sum += atoi(num.c_str());
//             dfs(root->right,num);
//         }
        else{
            dfs(root->left,num);
            dfs(root->right,num);
        }
    }
    int sumNumbers(TreeNode* root) {
        // write code here
        if(root == NULL)
            return 0;
        dfs(root,"");
        return sum;
    }
};