Merge pull request #219 from sir-gon/feature/two-strings

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

Author: sir-gon

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

@@ -0,0 +1,41 @@
+package ae.hackerrank.interview_preparation_kit.dictionaries_and_hashmaps;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * TwoStrings.
+ *
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two-strings.md]]
+ * @link Solution notes [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two-strings-solution-notes.md]]
+ */
+public class TwoStrings {
+  private TwoStrings() {}
+
+  private static final String YES = "YES";
+  private static final String NO = "NO";
+
+  /**
+   * twoStringsCompute.
+   */
+  public static boolean twoStringsCompute(String s1, String s2) {
+
+    Set<String> dictionary = new HashSet<>();
+
+    for (char occurrence : s1.toCharArray()) {
+      dictionary.add("%c".formatted(occurrence));
+    }
+
+    for (char occurrence : s2.toCharArray()) {
+      if (dictionary.contains("%c".formatted(occurrence))) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  public static String twoStrings(String s1, String s2) {
+    return twoStringsCompute(s1, s2) ? YES : NO;
+  }
+}

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

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+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;
+
+/**
+ * TwoStringsTest.
+*/
+@TestInstance(Lifecycle.PER_CLASS)
+class TwoStringsTest {
+  public static class TwoStringsTestCase {
+    public String title;
+    public String s1;
+    public String s2;
+    public String expected;
+  }
+
+  private List<TwoStringsTestCase> testCases;
+
+  @BeforeAll
+  public void setup() throws IOException {
+    String path = String.join("/",
+         "hackerrank",
+        "interview_preparation_kit",
+        "dictionaries_and_hashmaps",
+        "two_strings.testcases.json");
+
+    this.testCases = JsonLoader.loadJson(path, TwoStringsTestCase.class);
+  }
+
+  @Test void testTwoStrings() {
+    for (TwoStringsTestCase test : testCases) {
+      String solutionFound = TwoStrings.twoStrings(test.s1, test.s2);
+
+      assertEquals(test.expected, solutionFound,
+          String.format("%s(%s, %s) answer must be: %s",
+            "CrushOptimized.arrayManipulation",
+            test.s1,
+            test.s2,
+            test.expected
+          )
+      );
+    }
+  }
+}

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

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+[
+  {
+    "title": "Example 1",
+    "s1": "and",
+    "s2": "art",
+    "expected": "YES"
+  },
+  {
+    "title": "Example 2",
+    "s1": "be",
+    "s2": "cat",
+    "expected": "NO"
+  },
+  {
+    "title": "Sample Test Case 0",
+    "s1": "hello",
+    "s2": "world",
+    "expected": "YES"
+  }
+]

docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two-strings-solution-notes.md

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+# [Two Strings](https://www.hackerrank.com/challenges/two-strings)
+
+- Difficulty:  `#easy`
+- Category: `#ProblemSolvingBasic` `#dictionaries` `#hashmaps`
+
+## Clarification
+
+The problem asks to find if there is a substring between 2 words,
+it does not require finding a particular one that meets a certain property,
+not counting all the possible ones.
+
+With that in mind, simply find the first 1-letter intersection between two word
+to return "YES".
+The worst case is to return "NO" after going through both words letter by letter.

docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two-strings.md

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+# [Two Strings](https://www.hackerrank.com/challenges/two-strings)
+
+- Difficulty:  `#easy`
+- Category: `#ProblemSolvingBasic` `#dictionaries` `#hashmaps`
+
+Given two strings, determine if they share a common substring.
+A substring may be as small as one character.
+
+## Example
+
+`s1 = 'and'`
+`s1 = 'art'`
+
+These share the common substring `a`.
+
+`s1 = 'be'`
+`s1 = 'cat'`
+
+These do not share a substring.
+
+## Function Description
+
+Complete the function twoStrings in the editor below.
+
+twoStrings has the following parameter(s):
+
+- `string s1`: a string
+- `string s2`: another string
+
+## Returns
+
+- `string`: either YES or NO
+
+## Input Format
+
+The first line contains a single integer , the number of test cases.
+
+The following  pairs of lines are as follows:
+
+The first line contains string `s1`.
+The second line contains string `s2`.
+
+## Constraints
+
+- `s1` and `s2` consist of characters in the range ascii[a-z].
+- $ 1 \leq p \leq 10 $
+- $ 1 \leq |s1|, |s2| \leq 10^5 $
+
+## Output Format
+
+For each pair of strings, return `YES` or `NO`.
+
+## Sample Input
+
+```text
+2
+hello
+world
+hi
+world
+```
+
+## Sample Output
+
+```text
+YES
+NO
+```
+
+## Explanation
+
+We have  pairs to check:
+
+1. `s1 = "hello"`, `s2 = "world"`. The substrings `"o"` and `"l"`
+are common to both strings.
+2. `a = "hi"`, `b = "world"`. `s1` and `s2` share no common substrings.
+
+## Appendix
+
+[Solution notes](two-strings-solution-notes.md)