String Rotation

Author: premaseem

src/crackingTheCodingInterview/chap1/StringRotation.java

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+package crackingTheCodingInterview.chap1;
+
+import org.junit.Test;
+
+/**
+ * ### String Rotation:
+ * Assume you have a method isSubstringwhich checks if one word is a substring of another.
+ * Given two strings, sl and s2, write code to check if s2 is a rotation of sl using only one call to isSubstring
+ * (e.g.,"waterbottle" is a rotation of "erbottlewat").
+ */
+public class StringRotation {
+    // Test Driven Development by Aseem Jain
+    @Test
+    public void test() {
+
+        assert solution1("waterbottle", "erbottlewat");
+        assert solution1("apple", "pleap");
+        assert !solution1("camera", "macera");
+
+    }
+
+    // Basic solution
+    private boolean solution1(String s1, String s2) {
+        if (s1.length() != s2.length()) {
+            return false;
+        }
+
+        String dobuleString = s1 + s1;
+        // make sure s2 is part of s1
+        return dobuleString.contains(s2);
+    }
+
+}