add new solutions

solutions/11/q1137/solution.go

@@ -0,0 +1,14 @@
+package q1137
+
+func tribonacci(n int) int {
+	a := [3]int{0, 1, 1}
+	if n < 3 {
+		return a[n]
+	}
+	for range n - 3 + 1 {
+		a = [3]int{a[1], a[2], a[0] + a[1] + a[2]}
+	}
+	return a[2]
+}
+
+var _ = tribonacci