[Hacker Rank] Interview Preparation Kit: Dictionaries and Hashmaps: H…

algorithm-exercises-java/src/main/java/ae/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/RansomNote.java

@@ -0,0 +1,63 @@
+package ae.hackerrank.interview_preparation_kit.dictionaries_and_hashmaps;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import util.Log;
+
+/**
+ * RansomNote.
+ *
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md]]
+ */
+public class RansomNote {
+  /**
+   * InvalidValueException.
+   */
+  public class InvalidValueException extends Exception {
+    // constructor for the InvalidAgeException class
+    public InvalidValueException(String msg) {
+      Log.error(msg);
+    }
+  }
+
+  protected RansomNote() {
+  }
+
+  private static final String YES = "Yes";
+  private static final String NO = "No";
+
+  /**
+   * checkMagazineCompute.
+   */
+  public static boolean checkMagazineCompute(List<String> magazine, List<String> note) {
+    Map<String, Integer> dictionary = new HashMap<>();
+
+    for (String word : magazine) {
+      if (dictionary.putIfAbsent(word, 1) != null) {
+        Integer currentValue = dictionary.get(word);
+        dictionary.put(word, currentValue + 1);
+      }
+    }
+
+    for (String word : note) {
+      try {
+        dictionary.put(word, dictionary.get(word) - 1);
+        if (dictionary.get(word) < 0) {
+          throw new RansomNote().new InvalidValueException("Value can't go below 0");
+        }
+      } catch (Exception e) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  /**
+   * checkMagazine.
+   */
+  public static String checkMagazine(List<String> magazine, List<String> note) {
+    return checkMagazineCompute(magazine, note) ? YES : NO;
+  }
+}

algorithm-exercises-java/src/test/java/ae/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/RansomNoteTest.java

@@ -0,0 +1,49 @@
+package ae.hackerrank.interview_preparation_kit.dictionaries_and_hashmaps;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.util.List;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+import util.JsonLoader;
+
+@TestInstance(Lifecycle.PER_CLASS)
+class RansomNoteTest {
+
+  public static class RansomNoteTestCase {
+    public String title;
+    public List<String> magazine;
+    public List<String> note;
+    public String expected;
+  }
+
+  List<RansomNoteTestCase> testCases;
+
+  @BeforeAll
+  public void setup() throws IOException {
+    String path = String.join("/", "hackerrank",
+        "interview_preparation_kit",
+        "dictionaries_and_hashmaps",
+        "ctci_ransom_note.testcases.json");
+
+    this.testCases = JsonLoader.loadJson(path, RansomNoteTestCase.class);
+  }
+
+  @Test void testArrayManipulation() {
+    for (RansomNoteTestCase test : testCases) {
+      String solutionFound = RansomNote.checkMagazine(test.magazine, test.note);
+
+      assertEquals(test.expected, solutionFound,
+          String.format("%s(%s, %s) answer must be: %s",
+            "CrushOptimized.arrayManipulation",
+            test.magazine,
+            test.note,
+            test.expected
+          )
+      );
+    }
+  }
+}

algorithm-exercises-java/src/test/resources/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci_ransom_note.testcases.json

@@ -0,0 +1,20 @@
+[
+  {
+    "title": "Sample Test Case 0",
+    "magazine": ["give", "me", "one", "grand", "today", "night"],
+    "note": ["give", "one", "grand", "today"],
+    "expected": "Yes"
+  },
+  {
+    "title": "Sample Test Case 1",
+    "magazine": ["two", "times", "three", "is", "not", "four"],
+    "note": ["two", "times", "two", "is", "four"],
+    "expected": "No"
+  },
+  {
+    "title": "Sample Test",
+    "magazine": ["two", "two", "times", "three", "is", "not", "four"],
+    "note": ["two", "times", "two", "is", "four"],
+    "expected": "Yes"
+  }
+]

docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md

@@ -0,0 +1,102 @@
+# [Hash Tables: Ransom Notes](https://www.hackerrank.com/challenges/ctci-ransom-note)
+
+- Difficulty:  `#easy`
+- Category: `#ProblemSolvingIntermediate` `#dictionaries` `#hashmaps`
+
+Harold is a kidnapper who wrote a ransom note, but now he is worried it will be
+traced back to him through his handwriting. He found a magazine and wants to
+know if he can cut out whole words from it and use them to create an untraceable
+replica of his ransom note.
+The words in his note are case-sensitive and he must use only whole words
+available in the magazine.
+He cannot use substrings or concatenation to create the words he needs.
+
+Given the words in the magazine and the words in the ransom note,
+print `Yes` if he can replicate his ransom note exactly using whole words
+from the magazine; otherwise, print `No`.
+
+## Example
+
+`magazine` = "attack at dawn"  `note` = "Attack at dawn"
+
+The magazine has all the right words, but there is a case mismatch.
+The answer is `No`.
+
+## Function Description
+
+Complete the checkMagazine function in the editor below.
+It must print `Yes` if the note can be formed using the magazine, or .
+
+checkMagazine has the following parameters:
+
+- `string magazine[m]`: the words in the magazine
+- `string note[n]`: the words in the ransom note
+
+## Prints
+
+- string: either  or , no return value is expected
+
+## Input Format
+
+The first line contains two space-separated integers, `m` and `n`,
+the numbers of words in the  and the , respectively.
+
+The second line contains `m` space-separated strings, each `magazine[i]`.
+
+The third line contains `n` space-separated strings, each `node[i]`.
+
+## Constraints
+
+- $ 1 \leq m, n \leq 30000 $
+- $ 1 \leq $ length of `magazine[i]` and `note[i]` $ \leq 5 $
+- Each word consists of English alphabetic letters (i.e., `a` to `z` and `A` to `Z`).
+
+## Sample Input 0
+
+```text
+6 4
+give me one grand today night
+give one grand today
+```
+
+## Sample Output 0
+
+```text
+Yes
+```
+
+## Sample Input 1
+
+```text
+6 5
+two times three is not four
+two times two is four
+```
+
+## Sample Output 1
+
+```text
+No
+```
+
+## Explanation 1
+
+'two' only occurs once in the magazine.
+
+## Sample Input 2
+
+```text
+7 4
+ive got a lovely bunch of coconuts
+ive got some coconuts
+```
+
+## Sample Output 2
+
+```text
+No
+```
+
+## Explanation 2
+
+Harold's magazine is missing the word `some`.