题解 | #在二叉树中找到两个节点的最近公共祖先#

public int lowestCommonAncestor (TreeNode root, int o1, int o2) {
        // write code here
        if(root==null)return -1;
        if(root.val==o1||root.val==o2)return root.val;
        int left = lowestCommonAncestor(root.left,o1,o2);
        int right = lowestCommonAncestor(root.right,o1,o2);
        if(left==-1)return right;
        if(right==-1)return left;
        return root.val;//左右子树均非空，说明在此结点两侧（=最近公共祖先）
    }