标签：turn tor roo code null family comm solution mil
3
/ 5 1
/ \ / 6 2 0 8
/ 7 4
如上图所示，5和1的祖先是3，5和4的祖先是5；6和4的祖先是5；
1 public class Solution { 2 public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { 3 if(root == null) return null; 4 if(root ==p || root == q) //如果root是结点p或者q，返回结点p或者q； 5 return root; 6 TreeNode l = lowestCommonAncestor(root.left,p,q); //返回null，说明节点p和节点q都不在root.left分支；如果l！= null，至少有一个结点在左分支 7 TreeNode r = lowestCommonAncestor(root.right,p,q);//如果r！=null，至少有一个节点在右分支上 8 if(l == null) 9 return r; 10 if(r == null) 11 return l; 12 13 return root; 14 15 } 16 }
2. Lowest Common Ancestor of a Binary Search Tree
_______6______
/ ___2__ ___8__
/ \ / 0 _4 7 9
/ 3 5
代码如下：
1 public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { 2 while((root.val-p.val)*(root.val-q.val)>0){ 3 root = root.val>p.val?root.left:root.right; 4 } //就一直找到第一个root使得(root.val-p.val)*(root.val-q.val)<=0 为止
5 return root; 6 }
Lowest Common Ancestor of a Binary Search Tree
标签：turn tor roo code null family comm solution mil
原文地址：http://www.cnblogs.com/zhihuayun/p/6931191.html
