二叉树中和为某一值的路径
C++，简单的dfs，其实想不清楚为什么没有排序也能过。。。
代码：
/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
vector<vector<int>> FindPath(TreeNode* root,int expectNumber) {
vector<vector<int>> ans;
vector<int> path;
if (!root) return ans;
dfs(root, expectNumber, 0, path, ans);
return ans;
}
void dfs(TreeNode *root, int &sum, int tsum, vector<int> &path, vector<vector<int>> &ans) {
path.push_back(root->val);
tsum += root->val;
if (root->left)
dfs(root->left, sum, tsum, path, ans);
if (root->right)
dfs(root->right, sum, tsum, path, ans);
if (!root->left && !root->right)
if (tsum == sum)
ans.push_back(path);
path.pop_back();
}
};
