[LeetCode]--235. Lowest Common Ancestor of a Binary Search Tree

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.

According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has both v and w as descendants (where we allow a node to be a descendant of itself).”

     _______6______
    /              \
 ___2__          ___8__
/      \        /      \
0      4       7       9
      /  \
     3   5

For example, the lowest common ancestor (LCA) of nodes 2 and 8 is 6. Another example is LCA of nodes 2 and 4 is 2, since a node can be a descendant of itself according to the LCA definition.

思路就是找到一个节点的所有父节点，放在一个队列里面。然后两个节点的所有父节点形成的两个队列找到分叉（最后一个相同的节点），就是最近的一个父节点。