题解 | #二叉树中和为某一值的路径(二)#

• 前序遍历，记录每条路径；
• 当前路径和满足目标值（无左右子节点），将当前路径放入结果中。

/*
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(NULL), right(NULL) {
	}
};*/
class Solution {
public:
    
    void traversal(TreeNode* root, int expectNumber, vector<int>& path, vector<vector<int>>& result) {
        path.push_back(root->val);
        if (root->val == expectNumber && root->left == NULL && root->right == NULL) {
            result.push_back(path);
            return;
        }
        if (root->left) {
            traversal(root->left, expectNumber - root->val, path, result);
            path.pop_back();
        }
        if (root->right) {
            traversal(root->right, expectNumber - root->val, path, result);
            path.pop_back();
        }
        
    }
    vector<vector<int> > FindPath(TreeNode* root,int expectNumber) {
        vector<vector<int>> result;
        vector<int> path;
        if (root == NULL) return result;
        traversal(root, expectNumber, path, result);
        return result;
    }
};