tree.cpp

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
struct TreeNode {
	int val;
	TreeNode *left;
	TreeNode *right;
	TreeNode(int x) : val(x), left(nullptr), right(nullptr){}
};
static inline bool isLeaf(TreeNode *root)
{
	return root->left == NULL && root->right == NULL;
}
class Solution {
public:
	int sumNumbers(TreeNode *root) {
		return sumNumbers(root, 0);
	}
	int sumNumbers1(TreeNode *root) {
		if (root == NULL)
			return 0;
		vector<int> numbers;
		getNumbers(numbers, root, 0);
		int sum = 0;
		for_each(numbers.begin(), numbers.end(), [&sum](int value){sum += value;});
		return sum;
	}
private:
	int sumNumbers(TreeNode *root, int sum) {
		if (root == NULL)
			return 0;
		sum = sum * 10 + root->val;
		if (isLeaf(root)) {
			return sum;
		} else {
			return sumNumbers(root->left, sum) + sumNumbers(root->right, sum);
		}
	}
	void getNumbers(vector<int> &result, TreeNode *root, int number) {
		if (root == NULL)
			return;
		number *= 10;
		number += root->val;
		if (isLeaf(root)) {
			result.push_back(number);
		} else {
			getNumbers(result, root->left, number);
			getNumbers(result, root->right, number);
		}
	}
};
TreeNode *mk_node(int val)
{
	return new TreeNode(val);
}
TreeNode *mk_child(TreeNode *root, TreeNode *left, TreeNode *right)
{
	root->left = left;
	root->right = right;
	return root;
}
TreeNode *mk_child(TreeNode *root, int left, int right)
{
	return mk_child(root, new TreeNode(left), new TreeNode(right));
}
TreeNode *mk_child(int root, int left, int right)
{
	return mk_child(new TreeNode(root), new TreeNode(left), new TreeNode(right));
}
int main(int argc, char **argv)
{
	Solution solution;
	TreeNode *root = mk_child(mk_node(1), mk_node(0), nullptr);
	cout << solution.sumNumbers(root) << endl;
	return 0;
}