-
Notifications
You must be signed in to change notification settings - Fork 81
/
HouseRobberIII337.java
87 lines (77 loc) 路 2.07 KB
/
HouseRobberIII337.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
/**
* 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 1
*
* Maximum 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.
*
*/
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class HouseRobberIII337 {
public int rob(TreeNode root) {
return helper(root).last;
}
private DP helper(TreeNode root) {
if (root == null) {
return new DP(0, 0);
}
if (root.left == null && root.right == null) {
return new DP(root.val, 0);
}
DP leftDP = helper(root.left);
DP rightDP = helper(root.right);
return new DP(
Math.max(root.val+leftDP.prev+rightDP.prev, leftDP.last+rightDP.last),
leftDP.last+rightDP.last
);
}
class DP {
Integer last;
Integer prev;
DP(Integer last, Integer prev) {
this.last = last;
this.prev = prev;
}
}
public int rob2(TreeNode root) {
int[] res = helper2(root);
return res[1];
}
public int[] helper2(TreeNode root) {
if (root == null) return new int[]{0, 0};
int[] left = helper(root.left);
int[] right = helper(root.right);
return new int[]{left[1] + right[1], Math.max(left[0] + right[0] + root.val, left[1] + right[1])};
}
}