Add solution #1137

Author: JoshCrozier

README.md

@@ -381,6 +381,7 @@
 1103|[Distribute Candies to People](./1103-distribute-candies-to-people.js)|Easy|
 1108|[Defanging an IP Address](./1108-defanging-an-ip-address.js)|Easy|
 1122|[Relative Sort Array](./1122-relative-sort-array.js)|Easy|
+1137|[N-th Tribonacci Number](./1137-n-th-tribonacci-number.js)|Easy|
 1161|[Maximum Level Sum of a Binary Tree](./1161-maximum-level-sum-of-a-binary-tree.js)|Medium|
 1189|[Maximum Number of Balloons](./1189-maximum-number-of-balloons.js)|Easy|
 1200|[Minimum Absolute Difference](./1200-minimum-absolute-difference.js)|Easy|

solutions/1137-n-th-tribonacci-number.js

@@ -0,0 +1,25 @@
+/**
+ * 1137. N-th Tribonacci Number
+ * https://leetcode.com/problems/n-th-tribonacci-number/
+ * Difficulty: Easy
+ *
+ * The Tribonacci sequence Tn is defined as follows:
+ *
+ * T0 = 0, T1 = 1, T2 = 1, and Tn+3 = Tn + Tn+1 + Tn+2 for n >= 0.
+ *
+ * Given n, return the value of Tn.
+ */
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var tribonacci = function(n) {
+  const nums = [0, 1, 1];
+
+  for (let i = 3; i <= n; i++) {
+    nums.push(nums[i - 3] + nums[i - 2] + nums[i - 1]);
+  }
+
+  return nums[n];
+};