[Hacker Rank]: Warmup: Diagonal Difference. Solved ✅.

docs/hackerrank/warmup/diagonal_difference.md

@@ -0,0 +1,86 @@
+# [Diagonal Difference](https://www.hackerrank.com/challenges/diagonal-difference)
+
+Difficulty: #easy
+Category: #warmup
+
+Given a square matrix, calculate the absolute difference between the sums
+of its diagonals.
+For example, the square matrix $ arr $ is shown below:
+
+```text
+1 2 3
+4 5 6
+9 8 9
+```
+
+The left-to-right $ diagonal = 1 + 5 + 9 = 15 $.
+The right to left $ diagonal = 3 + 5 + 9 = 17 $.
+Their absolute difference is $ |15 - 17| = 2 $.
+
+## Function description
+
+Complete the $ diagonalDifference $ function in the editor below.
+diagonalDifference takes the following parameter:
+
+- int ` arr[n][m] `: an array of integers
+
+## Return
+
+- int: the absolute diagonal difference
+
+## Input Format
+
+The first line contains a single integer, n, the number of
+rows and columns in the square matrix arr.
+Each of the next n lines describes a row, arr[i], and consists of
+space-separated integers ` arr[i][j] `.
+
+## Constraints
+
+$ -100 \leq $ ` arr[i][j] ` $ \leq 100 $
+
+## Output Format
+
+Return the absolute difference between the sums of the matrix's
+two diagonals as a single integer.
+
+## Sample Input
+
+```text
+3
+11 2 4
+4 5 6
+10 8 -12
+```
+
+Sample Output
+
+```text
+15
+```
+
+## Explanation
+
+The primary diagonal is:
+
+```text
+11
+   5
+     -12
+```
+
+Sum across the primary diagonal: 11 + 5 - 12 = 4
+The secondary diagonal is:
+
+```text
+     4
+   5
+10
+```
+
+Sum across the secondary diagonal: $ 4 + 5 + 10 = 19 $
+Difference: $ |4 - 19| = 15 $
+
+*Note*: $ |x| $ is the
+[absolute value](https://www.mathsisfun.com/numbers/absolute-value.html)
+of $ x $

src/lib/exercises/include/exercises/hackerrank/warmup/diagonal_difference.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int HACKERRANK_WARMUP_diagonalDifference(int arr_rows, int arr_columns,
+                                         int **arr);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif

src/lib/exercises/src/hackerrank/warmup/diagonal_difference.c

@@ -0,0 +1,24 @@
+#include <exercises/hackerrank/warmup/diagonal_difference.h>
+
+/**
+ * @link Problem definition [[docs/hackerrank/warmup/diagonal_difference.md]]
+ */
+
+#include <stdlib.h>
+
+int HACKERRANK_WARMUP_diagonalDifference(int arr_rows, int arr_columns,
+                                         int **arr) {
+  int diag1 = 0;
+  int diag2 = 0;
+  int last = arr_rows - 1L;
+
+  for (int i = 0; i < arr_rows; i++) {
+    for (int j = 0; j < arr_columns; j++) {
+      if (i == j) {
+        diag1 += arr[i][j];
+        diag2 += arr[last - i][j];
+      }
+    }
+  }
+  return abs(diag1 - diag2);
+}

src/tests/unit/lib/hackerrank/warmup/diagonal_difference.test.cpp

@@ -0,0 +1,65 @@
+#include <catch2/catch_test_macros.hpp>
+
+#include <exercises/hackerrank/warmup/diagonal_difference.h>
+#include <iostream>
+#include <vector>
+
+#include <filesystem>
+#include <fstream>
+#include <nlohmann/json.hpp>
+using json = nlohmann::json;
+
+int **jsonToMatrix(const nlohmann::json &matrixJson, int &rows, int &cols) {
+  // Extraer dimensiones
+  rows = matrixJson.size();
+  cols = rows > 0 ? matrixJson[0].size() : 0;
+
+  // Crear matriz dinámica
+  int **matrix = new int *[rows];
+  for (int i = 0; i < rows; ++i) {
+    matrix[i] = new int[cols];
+    for (int j = 0; j < cols; ++j) {
+      matrix[i][j] = matrixJson[i][j];
+    }
+  }
+
+  return matrix;
+}
+
+void freeMatrix(int **matrix, int rows) {
+  for (int i = 0; i < rows; ++i) {
+    delete[] matrix[i];
+  }
+  delete[] matrix;
+}
+
+TEST_CASE("diagonalDifference JSON Test Cases",
+          "[hackerrank] [jsontestcase] [warmup]") {
+  std::filesystem::path cwd = std::filesystem::current_path();
+  std::string path =
+      cwd.string() +
+      "/unit/lib/hackerrank/warmup/diagonal_difference.testcases.json";
+
+  INFO("diagonalDifference JSON test cases FILE: " << path);
+
+  std::ifstream f(path);
+  nlohmann::json testCases = nlohmann::json::parse(f);
+
+  // Iterar sobre los casos de prueba
+  for (const auto &testCase : testCases) {
+    const auto &matrixJson = testCase["matrix"];
+    int expected = testCase["expected"];
+
+    int rows, cols;
+    int **matrix = jsonToMatrix(matrixJson, rows, cols);
+
+    // Llamar a la función bajo prueba
+    int result = HACKERRANK_WARMUP_diagonalDifference(rows, cols, matrix);
+
+    // Validar el resultado
+    REQUIRE(result == expected);
+
+    // Liberar memoria de la matriz
+    freeMatrix(matrix, rows);
+  }
+}

src/tests/unit/lib/hackerrank/warmup/diagonal_difference.testcases.json

@@ -0,0 +1,10 @@
+[
+  { "matrix":
+    [
+      [11, 2, 4],
+      [4, 5, 6],
+      [10, 8, -12]
+    ],
+    "expected": 15
+  }
+]