Add solution #1411

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,287 LeetCode solutions in JavaScript
+# 1,288 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1078,6 +1078,7 @@
 1408|[String Matching in an Array](./solutions/1408-string-matching-in-an-array.js)|Easy|
 1409|[Queries on a Permutation With Key](./solutions/1409-queries-on-a-permutation-with-key.js)|Medium|
 1410|[HTML Entity Parser](./solutions/1410-html-entity-parser.js)|Medium|
+1411|[Number of Ways to Paint N × 3 Grid](./solutions/1411-number-of-ways-to-paint-n-3-grid.js)|Hard|
 1415|[The k-th Lexicographical String of All Happy Strings of Length n](./solutions/1415-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n.js)|Medium|
 1422|[Maximum Score After Splitting a String](./solutions/1422-maximum-score-after-splitting-a-string.js)|Easy|
 1431|[Kids With the Greatest Number of Candies](./solutions/1431-kids-with-the-greatest-number-of-candies.js)|Easy|

solutions/1411-number-of-ways-to-paint-n-3-grid.js

@@ -0,0 +1,31 @@
+/**
+ * 1411. Number of Ways to Paint N × 3 Grid
+ * https://leetcode.com/problems/number-of-ways-to-paint-n-3-grid/
+ * Difficulty: Hard
+ *
+ * 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 109 + 7.
+ */
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var numOfWays = function(n) {
+  const MOD = 1000000007n;
+  let pattern121 = 6n;
+  let pattern123 = 6n;
+
+  for (let row = 2; row <= n; row++) {
+    const nextPattern121 = (3n * pattern121 + 2n * pattern123) % MOD;
+    const nextPattern123 = (2n * pattern121 + 2n * pattern123) % MOD;
+    pattern121 = nextPattern121;
+    pattern123 = nextPattern123;
+  }
+
+  return Number((pattern121 + pattern123) % MOD);
+};