From ab8249dbc6c46bf85ad20b4ad5eb603482c06ecd Mon Sep 17 00:00:00 2001
From: Erocs <github@erocs.org>
Date: Fri, 20 Jan 2017 13:10:58 -0800
Subject: [PATCH] [Go] Challenge 13 (Unreviewed)

---
 challenge_13/go/erocs/README.md           | 12 +++++
 challenge_13/go/erocs/src/c13/c13.go      | 24 ++++++++++
 challenge_13/go/erocs/src/c13/c13_test.go | 55 +++++++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 challenge_13/go/erocs/README.md
 create mode 100644 challenge_13/go/erocs/src/c13/c13.go
 create mode 100644 challenge_13/go/erocs/src/c13/c13_test.go

diff --git a/challenge_13/go/erocs/README.md b/challenge_13/go/erocs/README.md
new file mode 100644
index 000000000..25f54b71e
--- /dev/null
+++ b/challenge_13/go/erocs/README.md
@@ -0,0 +1,12 @@
+# Challenge 13: Integer Palindrome
+
+## 1. Solution Description
+
+Divide the given value by 10 until it is 0 to extract all digits and store those into a slice. Then just check that each element of the first half of the slice is mirrored on the other half.
+
+## 2. Running Tests
+
+In bash in this directory:
+
+    export GOPATH=`pwd`
+    go test c13
diff --git a/challenge_13/go/erocs/src/c13/c13.go b/challenge_13/go/erocs/src/c13/c13.go
new file mode 100644
index 000000000..5a353ff81
--- /dev/null
+++ b/challenge_13/go/erocs/src/c13/c13.go
@@ -0,0 +1,24 @@
+package c13
+
+func splitDigits(n uint64, base uint64) []byte {
+	out := make([]byte, 0, 22) // 22 is max length base-8 represented 64-bit value
+	for n > 0 {
+		r := n % base
+		n = n / base
+		out = append(out, byte(r))
+	}
+	return out
+}
+
+func IsPalindrome64(n uint64) bool {
+	ds := splitDigits(n, 10)
+	ll := len(ds)
+	hl := ll / 2
+	ll--
+	for i := 0; i < hl; i++ {
+		if ds[i] != ds[ll-i] {
+			return false
+		}
+	}
+	return true
+}
diff --git a/challenge_13/go/erocs/src/c13/c13_test.go b/challenge_13/go/erocs/src/c13/c13_test.go
new file mode 100644
index 000000000..64d9b8c27
--- /dev/null
+++ b/challenge_13/go/erocs/src/c13/c13_test.go
@@ -0,0 +1,55 @@
+package c13
+
+import (
+	"testing"
+)
+
+func CheckGood(t *testing.T, n uint64) {
+	if !IsPalindrome64(n) {
+		t.Fail()
+	}
+}
+
+func CheckBad(t *testing.T, n uint64) {
+	if IsPalindrome64(n) {
+		t.Fail()
+	}
+}
+
+func TestGL1(t *testing.T) {
+	CheckGood(t, 1)
+}
+
+func TestGL2(t *testing.T) {
+	CheckGood(t, 11)
+}
+
+func TestGL3(t *testing.T) {
+	CheckGood(t, 121)
+}
+
+func TestGL4(t *testing.T) {
+	CheckGood(t, 1221)
+}
+
+func TestBL2(t *testing.T) {
+	CheckBad(t, 12)
+}
+
+func TestBL3(t *testing.T) {
+	CheckBad(t, 112)
+}
+
+func TestBL4(t *testing.T) {
+	CheckBad(t, 1112)
+	CheckBad(t, 1121)
+}
+
+func TestGMax(t *testing.T) {
+	CheckGood(t, 11111111111111111111)
+}
+
+func TestBMax(t *testing.T) {
+	CheckBad(t, 11111111111111111112)
+	CheckBad(t, 11111111112111111111)
+}