[Hacker Rank] Interview Preparation Kit: Dictionaries and Hashmaps: Hash Tables: Two Strings. Solved ✓.

Author: Gonzalo Diaz

algorithm-exercises-csharp-test/src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/TwoStrings.Test.cs

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+namespace algorithm_exercises_csharp.hackerrank.interview_preparation_kit;
+
+[TestClass]
+public class TwoStringsTest
+{
+  public class TwoStringsTestCase
+  {
+    public string title = "";
+    public string s1 = "";
+    public string s2 = "";
+    public string expected = "Yes";
+  }
+
+  private static readonly TwoStringsTestCase[] tests = [
+    new()
+    {
+      title = "Example 1",
+      s1 = "and",
+      s2 = "art",
+      expected = "Yes"
+    },
+    new()
+    {
+      title = "Example 2",
+      s1 = "be",
+      s2 = "cat",
+      expected = "No"
+    },
+    new()
+    {
+      title = "Sample Test Case 0",
+      s1 = "hello",
+      s2 = "world",
+      expected = "Yes"
+    },
+  ];
+
+  [TestMethod]
+  public void testTwoStrings()
+  {
+    string result;
+
+    foreach (TwoStringsTestCase test in tests)
+    {
+      result = TwoStrings.twoStrings(test.s1, test.s2);
+      Assert.AreEqual(test.expected, result);
+    }
+  }
+}

algorithm-exercises-csharp/src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/TwoStrings.cs

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+// @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md]]
+
+namespace algorithm_exercises_csharp.hackerrank.interview_preparation_kit;
+
+using System.Diagnostics.CodeAnalysis;
+
+public class TwoStrings
+{
+  [ExcludeFromCodeCoverage]
+  protected TwoStrings() { }
+
+  private static readonly string __YES__ = "Yes";
+  private static readonly string __NO__ = "No";
+  private static readonly char __EMPTY_CHAR__ = '\0';
+
+  public static bool twoStringsCompute(string s1, string s2)
+  {
+    char occurrence = s1.FirstOrDefault(c => s2.Contains(c), __EMPTY_CHAR__);
+
+    if (occurrence != __EMPTY_CHAR__)
+    {
+      return true;
+    }
+
+    return false;
+  }
+
+  public static string twoStrings(string s1, string s2)
+  {
+    return twoStringsCompute(s1, s2) ? __YES__ : __NO__;
+  }
+}

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`
+
+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)