.\337.house-robber-iii ok

侯利朋 · 侯利朋 · commit 6850a2339898 · 2019-08-30T20:29:51.000+08:00
diff --git a/337.house-robber-iii-680ms.go b/337.house-robber-iii-680ms.go
@@ -0,0 +1,37 @@
+/*
+ * @lc app=leetcode id=337 lang=golang
+ *
+ * [337] House Robber III
+ */
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+// (680 ms) √ Your runtime beats 27.08 %
+// 递归， 非DP实现
+func rob(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+
+	// 打劫root
+	val := root.Val
+	if root.Left != nil {
+		val += rob(root.Left.Left) + rob(root.Left.Right)
+	}
+	if root.Right != nil {
+		val += rob(root.Right.Left) + rob(root.Right.Right)
+	}
+	return max(val, rob(root.Left)+rob(root.Right)) // 返回打劫root和不打劫root的最大值
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
diff --git a/337.house-robber-iii-8ms.go b/337.house-robber-iii-8ms.go
@@ -0,0 +1,51 @@
+/*
+ * @lc app=leetcode id=337 lang=golang
+ *
+ * [337] House Robber III
+ */
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+//  8 ms, faster than 72.92%
+// 递归， 非DP实现
+// map 缓存加速
+func rob(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+	buf := make(map[*TreeNode]int)
+	return robmap(root, buf)
+}
+
+func robmap(root *TreeNode, buf map[*TreeNode]int) int {
+	if root == nil {
+		return 0
+	}
+	if buf[root] > 0 {
+		return buf[root]
+	}
+	// 打劫root
+	val := root.Val
+	if root.Left != nil {
+		val += robmap(root.Left.Left, buf) + robmap(root.Left.Right, buf)
+	}
+	if root.Right != nil {
+		val += robmap(root.Right.Left, buf) + robmap(root.Right.Right, buf)
+	}
+
+	rtn := max(val, robmap(root.Left, buf)+robmap(root.Right, buf))
+	buf[root] = rtn
+	return rtn // 返回打劫root和不打劫root的最大值
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
diff --git a/337.house-robber-iii.go b/337.house-robber-iii.go
@@ -0,0 +1,49 @@
+/*
+ * @lc app=leetcode id=337 lang=golang
+ *
+ * [337] House Robber III
+ */
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+//  待优化，吧下面的map去掉，找到dp之间的关系，就能进一步节省空间
+func rob(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+	buf := make(map[*TreeNode]int)
+	return robmap(root, buf)
+}
+
+func robmap(root *TreeNode, buf map[*TreeNode]int) int {
+	if root == nil {
+		return 0
+	}
+	if buf[root] > 0 {
+		return buf[root]
+	}
+	// 打劫root
+	val := root.Val
+	if root.Left != nil {
+		val += robmap(root.Left.Left, buf) + robmap(root.Left.Right, buf)
+	}
+	if root.Right != nil {
+		val += robmap(root.Right.Left, buf) + robmap(root.Right.Right, buf)
+	}
+
+	rtn := max(val, robmap(root.Left, buf)+robmap(root.Right, buf))
+	buf[root] = rtn
+	return rtn // 返回打劫root和不打劫root的最大值
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
