add: House Robber II

HouseRobberII/step1.md

@@ -0,0 +1,36 @@
+```go
+// DP
+// Thought there is a cycle of hourse
+// We need to break it to two parts, one it's remove the first house and the another remove the last house
+// Since those two house it connected
+// We need to keep two array of DP to track the num that we can reach
+// Time complexity: O(N) N: number of given nums
+// Space complexity: O(N) 
+// Time spend: 03:49
+package main
+func rob(nums []int) int {
+    if len(nums) == 1 {
+        return nums[0]
+    }
+
+    return max(robHouses(nums[1:]), robHouses(nums[:len(nums) - 1]))
+}
+
+func robHouses(nums []int) int {
+    dp := make([]int, len(nums) + 2)
+
+    for i := 2; i < len(dp); i++ {
+        dp[i] = max(dp[i - 2] + nums[i - 2], dp[i - 1])
+    }
+
+    return dp[len(dp) - 1]
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+
+    return b
+}
+```

HouseRobberII/step2.md

@@ -0,0 +1,29 @@
+```go 
+// Time spend: 02:21
+package main
+func rob(nums []int) int {
+    if len(nums) == 1 {
+        return nums[0]
+    }
+
+    return max(robHouses(nums[1:]), robHouses(nums[:len(nums) - 1]))
+}
+
+func robHouses(nums []int) int {
+    dp := make([]int, len(nums) + 2)
+
+    for i := 2; i < len(dp); i++ {
+        dp[i] = max(dp[i - 2] + nums[i - 2], dp[i - 1])
+    }
+
+    return dp[len(dp) - 1]
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+
+    return b
+}
+```

HouseRobberII/step3.md

@@ -0,0 +1,89 @@
+```go 
+// Time spend: 01:48
+package main
+func rob(nums []int) int {
+    if len(nums) == 1 {
+        return nums[0]
+    }
+
+    return max(robHouses(nums[1:]), robHouses(nums[:len(nums) - 1]))
+}
+
+func robHouses(nums []int) int {
+    dp := make([]int, len(nums) + 2)
+
+    for i := 2; i < len(dp); i++ {
+        dp[i] = max(dp[i - 2] + nums[i - 2], dp[i - 1])
+    }
+
+    return dp[len(dp) - 1]
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+
+    return b
+}
+```
+
+```go 
+// Time spend: 01:47
+package main
+func rob(nums []int) int {
+    if len(nums) == 1 {
+        return nums[0]
+    }
+
+    return max(robHouses(nums[1:]), robHouses(nums[:len(nums) - 1]))
+}
+
+func robHouses(nums []int) int {
+    dp := make([]int, len(nums) + 2)
+
+    for i := 2; i < len(dp); i++ {
+        dp[i] = max(dp[i - 2] + nums[i - 2], dp[i - 1])
+    }
+
+    return dp[len(dp) - 1]
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+
+    return b
+}
+```
+
+```go 
+// Time spend: 01:43
+package main
+func rob(nums []int) int {
+    if len(nums) == 1 {
+        return nums[0]
+    }
+
+    return max(robHouses(nums[1:]), robHouses(nums[:len(nums) - 1]))
+}
+
+func robHouses(nums []int) int {
+    dp := make([]int, len(nums) + 2)
+
+    for i := 2; i < len(dp); i++ {
+        dp[i] = max(dp[i - 2] + nums[i - 2], dp[i - 1])
+    }
+
+    return dp[len(dp) - 1]
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+
+    return b
+}
+```