LeetCode1022. 从根到叶的二进制数之和

class Solution {

public:

    int ans = 0;

    int sumRootToLeaf(TreeNode* root) {

        dfs(root,0);

        return ans;

    }

    void dfs(TreeNode*root,int cur){

        if(root== NULL) return ;

        if(root->left == NULL && root->right == NULL){

            cur += root->val;

            ans += cur;

        }

        dfs(root->left,(cur+root->val)*2);

        dfs(root->right,(cur+root->val)*2);

    }

};