Leetcode--Lowest Common Ancestor of a Binary Search Tree

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/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public TreeNode LowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        var pathP = new List<TreeNode>();
        Path(root, p, pathP);
        var pathQ = new List<TreeNode>();
        Path(root, q , pathQ);
		
        var i = 0;
        while(i < pathP.Count || i < pathQ.Count){
			if(i >= pathP.Count ||i >= pathQ.Count){
				return pathP[--i];
			}
			
            if(pathP[i].val == pathQ[i].val){
                i ++;
            }
            else{
                return pathP[--i];
            }
        }
        return null;
    }
    
    public void Path(TreeNode node, TreeNode n, IList<TreeNode> list){
        if(node == null){
            return ;
        }
        list.Add(node);
		if(n.val == node.val){
			return;
		}
        if(n.val < node.val){
            Path(node.left, n ,list);
        }
        else{
            Path(node.right, n ,list);
        }
    }
    
}

Leetcode--Lowest Common Ancestor of a Binary Search Tree

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原文地址：http://blog.csdn.net/lan_liang/article/details/50145263