数据结构与算法面试题二叉树路径查找

Posted 2022-01-19 zhiyong_will

题目来源“数据结构与算法面试题80道”。

问题分析：核心是树的遍历，注意题目中“路径”的定义，是从根节点到叶子节点。先序遍历正好是从根节点开始，因此可以利用先序遍历的过程来实现这个过程。

方法：

void print_vector(vector<BinaryTreeNode *> &v)
	vector<BinaryTreeNode *>::iterator it;
	for (it = v.begin(); it != v.end(); it ++)
		printf("%d\\t", (*it)->m_nValue);
	
	printf("\\n");


void pre_order_route(BinaryTreeNode *p, int num, vector<BinaryTreeNode *> &q, int &current)
	if (NULL == p) return;

	current += p->m_nValue;
	q.push_back(p);

	bool is_leaf = (NULL == p->m_pLeft) && (NULL == p->m_pRight);

	if (current == num && is_leaf)
		print_vector(q);
	
	
	if (NULL != p->m_pLeft)
		pre_order_route(p->m_pLeft, num, q, current);
	

	if (NULL != p->m_pRight)
		pre_order_route(p->m_pRight, num, q, current);
	
	
	current -= (*(q.end() - 1))->m_nValue;
	q.pop_back();



void print_route(BinaryTreeNode *root, int num)
	vector<BinaryTreeNode *> q;// 用队列保存已经访问过的节点
	int current = 0;
	pre_order_route(root, num, q, current);