Add: Repeated Substring Pattern

problems/repeated-substring-pattern/repeated_substring_pattern.go

@@ -1 +1,7 @@
 package repeated_substring_pattern
+
+import "strings"
+
+func repeatedSubstringPattern(s string) bool {
+return strings.Contains((s + s)[1:2*len(s)-1], s)
+}

problems/repeated-substring-pattern/repeated_substring_pattern_test.go

@@ -1 +1,54 @@
 package repeated_substring_pattern
+
+import "testing"
+
+type caseType struct {
+input string
+expected bool
+}
+
+func TestRepeatedSubstringPattern(t *testing.T) {
+tests := [...]caseType{
+{
+input: "a",
+expected: false,
+},
+{
+input: "abab",
+expected: true,
+},
+{
+input: "aba",
+expected: false,
+},
+{
+input: "abaaba",
+expected: true,
+},
+{
+input: "abcabcabcabc",
+expected: true,
+},
+{
+input: "abbaabbaabba",
+expected: true,
+},
+{
+input: "abcabcabcdabcabcabcdabcabcabcd",
+expected: true,
+},
+{
+input: "abaabaabac",
+expected: false,
+}, {
+input: "babbabbabbabbab",
+expected: true,
+},
+}
+for _, tc := range tests {
+output := repeatedSubstringPattern(tc.input)
+if output != tc.expected {
+t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+}
+}
+}