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 sumNumbers(TreeNode* root) {
        if(!root) return 0;
        int val=0;
        vector<int> path;
        dfs(root,val,path);
        int sum=0;
        for(int i=0;i<path.size();i++){
            sum+=path[i];
        }
        return sum;
    }
    void dfs(TreeNode* root,int val,vector<int>& path){
        val=val*10+root->val;
        if(!root->left && !root->right) path.push_back(val);
        if(root->left) dfs(root->left,val,path);
        if(root->right) dfs(root->right,val,path);
        val=(val-root->val)/10;
    }
};