Merge pull request #1282 from 0xff-dev/1411

Add solution and test-cases for problem 1411

Author: 6boris

leetcode/1401-1500/1411.Number-of-Ways-to-Paint-N-x-3-Grid/1.png

@@ -0,0 +1,30 @@
+# [1411.Number of Ways to Paint N × 3 Grid][title]
+
+## Description
+You have a `grid` of size `n x 3` and you want to paint each cell of the grid with exactly one of the three colors: **Red**, **Yellow**, or **Green** while making sure that no two adjacent cells have the same color (i.e., no two cells that share vertical or horizontal sides have the same color).
+
+Given `n` the number of rows of the `grid`, return the number of ways you can paint this grid. As the answer may grow large, the answer **must be** computed modulo `10^9 + 7`.
+
+**Example 1:**  
+
+![1](./1.png)
+
+```
+Input: n = 1
+Output: 12
+Explanation: There are 12 possible way to paint the grid as shown.
+```
+
+**Example 2:**
+
+```
+Input: n = 5000
+Output: 30228214
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]
+
+[title]: https://leetcode.com/problems/number-of-ways-to-paint-n-3-grid
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/1401-1500/1411.Number-of-Ways-to-Paint-N-x-3-Grid/README.md

@@ -1,5 +1,44 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+const mod = 1000000007
+
+func Solution(n int) int {
+	rel := [12][]int{
+		{1, 4, 10, 2, 5},
+		{0, 3, 6, 8, 11},
+		{0, 3, 6, 7},
+
+		{1, 7, 10, 2},
+		{0, 6, 9, 8},
+		{0, 6, 9, 7, 10},
+
+		{1, 4, 2, 5, 11},
+		{3, 2, 5, 11},
+		{9, 1, 4, 10},
+
+		{4, 5, 8, 11},
+		{0, 3, 5, 8, 11},
+		{1, 7, 10, 6, 9},
+	}
+	var dfs func(int, int) int
+	cache := make(map[[2]int]int)
+	dfs = func(parent, left int) int {
+		if left == 0 {
+			return 1
+		}
+		ans := 0
+		l := len(rel[parent])
+		key := [2]int{l, left}
+		if v, ok := cache[key]; ok {
+			return v
+		}
+		for _, next := range rel[parent] {
+			ans = (ans + dfs(next, left-1)) % mod
+		}
+		cache[key] = ans
+		return ans
+	}
+	a := (dfs(0, n-1) * 6) % mod
+	b := (dfs(2, n-1) * 6) % mod
+	return (a + b) % mod
 }

leetcode/1401-1500/1411.Number-of-Ways-to-Paint-N-x-3-Grid/Solution.go

@@ -10,12 +10,11 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", 1, 12},
+		{"TestCase2", 5000, 30228214},
 	}
 
 	//	开始测试
@@ -30,10 +29,10 @@ func TestSolution(t *testing.T) {
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }