LeetCode 113. Path Sum II

代码：

class Solution {public:    vector<vector<int> > pathSum(TreeNode *root, int sum)     {    if (root!=NULL && root->left==NULL && root->right==NULL && root->val==sum)    {    num.push_back(root->val);    ret.push_back(num);    num.pop_back();    } else if (root != NULL)    {    num.push_back(root->val);    pathSum(root->left, sum - root->val);    pathSum(root->right, sum - root->val);    num.pop_back();    }    return ret;    }private:vector<int> num;vector<vector<int>> ret;};