Create 1137-n-th-tribonacci-number.js

Author: everthis

1137-n-th-tribonacci-number.js

@@ -0,0 +1,12 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+const hash = {}
+const tribonacci = function(n) {
+  if(n === 0) return 0
+  if(n === 2 || n === 1) return 1
+  if(hash[n] != null) return hash[n]
+  let tmp = tribonacci(n - 3) + tribonacci(n - 2) + tribonacci(n - 1)
+  return hash[n] = tmp
+};