Binary Tree Paths

iteye_6755

于 2015-11-01 10:31:07 发布

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本文介绍了一种用于查找二叉树中所有从根节点到叶子节点路径的算法实现。通过递归方式遍历二叉树，收集路径并将其转换为字符串形式返回。示例代码演示了如何使用Java实现该算法。

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Given a binary tree, return all root-to-leaf paths.

For example, given the following binary tree:

All root-to-leaf paths are:

["1->2->5", "1->3"]

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
	List<String> res = new ArrayList<>();
    public List<String> binaryTreePaths(TreeNode root) {
        if (root != null) {
        	findPaths(root, String.valueOf(root.val));
        }
        return res;
    }
	private void findPaths(TreeNode root, String valueOf) {
		// TODO Auto-generated method stub
		if (root.left == null && root.right == null) {
			res.add(valueOf);
		}
		if (root.left != null) {
			findPaths(root.left, valueOf + "->" + root.left.val);
		}
		if (root.right != null) {
			findPaths(root.right, valueOf + "->" + root.right.val);
		}
	}
}