Leetcode_面试题04.06后继者_树

在搜索的过程中，如果找到了p就标记一下，如果标记位为true，那么就返回这个值就行了

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    boolean flag;
    TreeNode ans;

    public TreeNode inorderSuccessor(TreeNode root, TreeNode p) {
        flag = false;
        ans = null;
        find(root, p);
        return ans;
    }

    public void find(TreeNode root, TreeNode p) {
        if(root == null) {
            return;
        }
        find(root.left, p);
        if(ans != null) {
            return;
        }
        if(flag) {
            ans = root;
            return;
        }
        if(root.equals(p)) {
            flag = true;
        }
        find(root.right, p);
    }
}