diff --git a/arranging-coins/sol.go b/arranging-coins/sol.go
new file mode 100644
index 0000000..065de41
--- /dev/null
+++ b/arranging-coins/sol.go
@@ -0,0 +1,9 @@
+package main
+
+import "math"
+
+// Time: O(1) (assuming computer has float64 sqrt instruction)
+// Space: O(1)
+func arrangeCoins(n int) int {
+	return int(math.Sqrt(float64(2*n)+0.25) - 0.5)
+}