Yay problem 4 in Go

project-euler/go/4/problem4.go

@@ -0,0 +1,38 @@
+package main
+
+import "fmt"
+import "strconv"
+
+// https://github.com/daviskoh/go-code-challenges/tree/master/reverse_string
+func ReverseString(s string) string {
+	if len(s) < 2 {
+		return s
+	}
+
+	return s[len(s)-1:len(s)] + ReverseString(s[0:len(s)-1])
+}
+
+func isPalendrome(n int) bool {
+	testString := strconv.Itoa(n)
+	return testString == ReverseString(testString)
+}
+
+func problem4() int {
+	max := 0
+
+	for i := 100; i <= 999; i++ {
+		for j := 100; j <= 999; j++ {
+			result := i * j
+			if isPalendrome(i*j) && result > max {
+				max = result
+			}
+		}
+	}
+
+	return max
+}
+
+func main() {
+	result := problem4()
+	fmt.Println("Answer:", result)
+}

project-euler/go/4/problem4_test.go

@@ -0,0 +1,33 @@
+package main
+
+import "testing"
+
+func TestProblem4(t *testing.T) {
+	expected := 906609
+	got := problem4()
+	if got != expected {
+		t.Errorf("oh no! expected: %i got: %i", expected, got)
+	}
+}
+
+func TestIsPalendrome(t *testing.T) {
+	got := isPalendrome(101)
+	if got != true {
+		t.Errorf("oh no! expected: %i got: %i", true, got)
+	}
+
+	got = isPalendrome(1)
+	if got != true {
+		t.Errorf("oh no! expected: %i got: %i", true, got)
+	}
+
+	got = isPalendrome(11)
+	if got != true {
+		t.Errorf("oh no! expected: %i got: %i", true, got)
+	}
+
+	got = isPalendrome(12)
+	if got != false {
+		t.Errorf("oh no! expected: %i got: %i", true, got)
+	}
+}