4.7 Design an algorithm and write code to find the first common ancestor of two nodes in a binary tree. Avoid storing additional nodes in a data structure. NOTE: This is not necessarily a binary search tree.

LeetCode上的原題，請參見我之前的博客Lowest Common Ancestor of a Binary Tree 二叉樹的最小共同父節點。

本文轉自博客園Grandyang的博客，原文鏈接：二叉樹的最小共同父節點[CareerCup] 4.7 Lowest Common Ancestor of a Binary Search Tree ，如需轉載請自行聯系原博主。