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

Author: Gonzalo Diaz

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`
+
+## 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`
+
+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)

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two_strings.js

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+/**
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two-strings.md]]
+ */
+
+const __YES__ = 'YES';
+const __NO__ = 'NO';
+
+export function twoStringsCompute(s1, s2) {
+  for (const char of s1) {
+    if (s2.includes(char)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+export function twoStrings(s1, s2) {
+  return twoStringsCompute(s1, s2) ? __YES__ : __NO__;
+}
+
+export default { twoStrings };

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/two_strings.test.js

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+import { describe, expect, it } from '@jest/globals';
+import { logger as console } from '../../../logger.js';
+
+import { twoStrings } from './two_strings.js';
+
+const TEST_CASES = [
+  {
+    title: 'Example 1 and 2',
+    comparing: [
+      {
+        s1: 'and',
+        s2: 'art',
+        expected: 'YES'
+      },
+      {
+        s1: 'be',
+        s2: 'cat',
+        expected: 'NO'
+      }
+    ]
+  },
+  {
+    title: 'Sample Test Case 0',
+    comparing: [
+      {
+        s1: 'hello',
+        s2: 'world',
+        expected: 'YES'
+      },
+      {
+        s1: 'hi',
+        s2: 'world',
+        expected: 'NO'
+      }
+    ]
+  },
+  {
+    title: 'Sample Test Case 6',
+    comparing: [
+      {
+        s1: 'wouldyoulikefries',
+        s2: 'abcabcabcabcabcabc',
+        expected: 'NO'
+      },
+      {
+        s1: 'hackerrankcommunity',
+        s2: 'cdecdecdecde',
+        expected: 'YES'
+      },
+      {
+        s1: 'jackandjill',
+        s2: 'wentupthehill',
+        expected: 'YES'
+      },
+      {
+        s1: 'writetoyourparents',
+        s2: 'fghmqzldbc',
+        expected: 'NO'
+      }
+    ]
+  }
+];
+
+describe('two_strings', () => {
+  it('twoStrings test cases', () => {
+    expect.assertions(8);
+
+    TEST_CASES.forEach((testCase) => {
+      testCase.comparing.forEach((test) => {
+        const answer = twoStrings(test.s1, test.s2);
+
+        console.debug(
+          `checkMagazine(${test.s1}, ${test.s2}) solution found: ${answer}`
+        );
+
+        expect(answer).toStrictEqual(test.expected);
+      });
+    });
+  });
+});