The thief has found himself a new place for his thievery again. There is only one entrance to this area, called the "root." Besides the root, each house has one and only one parent house. After a tour, the smart thief realized that "all houses in this place forms a binary tree". It will automatically contact the police if two directly-linked houses were broken into on the same night.
Determine the maximum amount of money the thief can rob tonight without alerting the police.
Example 1:
3 / \ 2 3 \ \ 3 1Maximum amount of money the thief can rob = 3 + 3 + 1 = 7 .
Example 2:
3 / \ 4 5 / \ \ 1 3 1
Maximum amount of money the thief can rob = 4 + 5 = 9.
题解:有2中方式如下图:
code:
public class Solution {
public int rob(TreeNode root) {
if(root == null)
return 0;
int first = root.val,second = 0;
if(root.left != null)
{
first += rob(root.left.left);
first += rob(root.left.right);
second += rob(root.left);
}
if(root.right != null)
{
first += rob(root.right.left);
first += rob(root.right.right);
second += rob(root.right);
}
return first>second?first:second;
}
}