From 96f59f9f54fcee3abcbfdfc28fd92f68243507d5 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Sun, 13 Apr 2025 21:58:53 +0200
Subject: [PATCH] =?UTF-8?q?go:=20add=20=C2=AB1922.=20Count=20Good=20Number?=
=?UTF-8?q?s=C2=BB?=
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URL: https://leetcode.com/problems/count-good-numbers/
Signed-off-by: Matej Focko <me@mfocko.xyz>
---
go/count-good-numbers.go | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
create mode 100644 go/count-good-numbers.go
diff --git a/go/count-good-numbers.go b/go/count-good-numbers.go
new file mode 100644
index 0000000..c18bd3d
--- /dev/null
+++ b/go/count-good-numbers.go
@@ -0,0 +1,22 @@
+package main
+
+const (
+ MOD int64 = 1000000007
+)
+
+func countGoodNumbers(n int64) int {
+ quickmul := func(x, y int64) int64 {
+ res := int64(1)
+ for y > 0 {
+ if y%2 == 1 {
+ res = (res * x) % MOD
+ }
+ x = (x * x) % MOD
+ y /= 2
+ }
+
+ return res
+ }
+
+ return int((quickmul(5, (n+1)/2) * quickmul(4, n/2)) % MOD)
+}