Adds Selection sort implementation in JavaScript and TypeScript

Author: NisargChokshi45

JavaScript/algorithms/sorting/selectionsort.js

@@ -0,0 +1,75 @@
+/* Selection Sort
+
+Description: Selection sort is a simple comparison-based sorting algorithm. It works by repeatedly finding the minimum element from the unsorted portion of the array and placing it at the beginning. The algorithm divides the array into two parts: sorted and unsorted. In each iteration, it selects the smallest element from the unsorted part and swaps it with the first element of the unsorted part.
+
+Time Complexity: O(n²)
+
+Space Complexity: O(1)
+*/
+
+function selectionSort(arr) {
+  const n = arr.length;
+
+  for (let i = 0; i < n - 1; i++) {
+    let minIndex = i;
+
+    for (let j = i + 1; j < n; j++) {
+      if (arr[j] < arr[minIndex]) {
+        minIndex = j;
+      }
+    }
+
+    // Swap the found minimum element with the first element
+    if (minIndex !== i) {
+      [arr[i], arr[minIndex]] = [arr[minIndex], arr[i]];
+    }
+  }
+
+  return arr;
+}
+
+function runTests() {
+  console.log("---------- Selection Sort Test Cases ----------");
+
+  // Test 1: Regular unsorted array
+  const test1 = [64, 34, 25, 12, 22, 11, 90];
+  console.log("\nTest 1 - Original:", [...test1]);
+  console.log("Test 1 - Sorted:", selectionSort([...test1]));
+
+  // Test 2: Already sorted array
+  const test2 = [1, 2, 3, 4, 5];
+  console.log("\nTest 2 - Original:", [...test2]);
+  console.log("Test 2 - Sorted:", selectionSort([...test2]));
+
+  // Test 3: Reverse sorted array
+  const test3 = [5, 4, 3, 2, 1];
+  console.log("\nTest 3 - Original:", [...test3]);
+  console.log("Test 3 - Sorted:", selectionSort([...test3]));
+
+  // Test 4: Array with duplicates
+  const test4 = [3, 1, 4, 1, 5, 9, 2, 6, 5];
+  console.log("\nTest 4 - Original:", [...test4]);
+  console.log("Test 4 - Sorted:", selectionSort([...test4]));
+
+  // Test 5: Single element array
+  const test5 = [42];
+  console.log("\nTest 5 - Original:", [...test5]);
+  console.log("Test 5 - Sorted:", selectionSort([...test5]));
+
+  // Test 6: Empty array
+  const test6 = [];
+  console.log("\nTest 6 - Original:", [...test6]);
+  console.log("Test 6 - Sorted:", selectionSort([...test6]));
+
+  // Test 7: Two element array
+  const test7 = [2, 1];
+  console.log("\nTest 7 - Original:", [...test7]);
+  console.log("Test 7 - Sorted:", selectionSort([...test7]));
+
+  // Test 8: Array with negative numbers
+  const test8 = [-5, 2, -3, 8, -1, 0];
+  console.log("\nTest 8 - Original:", [...test8]);
+  console.log("Test 8 - Sorted:", selectionSort([...test8]));
+}
+
+runTests();

TypeScript/algorithms/sorting/selectionsort.ts

@@ -0,0 +1,75 @@
+/* Selection Sort
+
+Description: Selection sort is a simple comparison-based sorting algorithm. It works by repeatedly finding the minimum element from the unsorted portion of the array and placing it at the beginning. The algorithm divides the array into two parts: sorted and unsorted. In each iteration, it selects the smallest element from the unsorted part and swaps it with the first element of the unsorted part.
+
+Time Complexity: O(n²)
+
+Space Complexity: O(1)
+*/
+
+function selectionSort(arr: number[]): number[] {
+  const n: number = arr.length;
+
+  for (let i = 0; i < n - 1; i++) {
+    let minIndex: number = i;
+
+    for (let j = i + 1; j < n; j++) {
+      if (arr[j] < arr[minIndex]) {
+        minIndex = j;
+      }
+    }
+
+    // Swap the found minimum element with the first element
+    if (minIndex !== i) {
+      [arr[i], arr[minIndex]] = [arr[minIndex], arr[i]];
+    }
+  }
+
+  return arr;
+}
+
+function runTests(): void {
+  console.log("---------- Selection Sort Test Cases ----------");
+
+  // Test 1: Regular unsorted array
+  const test1: number[] = [64, 34, 25, 12, 22, 11, 90];
+  console.log("\nTest 1 - Original:", [...test1]);
+  console.log("Test 1 - Sorted:", selectionSort([...test1]));
+
+  // Test 2: Already sorted array
+  const test2: number[] = [1, 2, 3, 4, 5];
+  console.log("\nTest 2 - Original:", [...test2]);
+  console.log("Test 2 - Sorted:", selectionSort([...test2]));
+
+  // Test 3: Reverse sorted array
+  const test3: number[] = [5, 4, 3, 2, 1];
+  console.log("\nTest 3 - Original:", [...test3]);
+  console.log("Test 3 - Sorted:", selectionSort([...test3]));
+
+  // Test 4: Array with duplicates
+  const test4: number[] = [3, 1, 4, 1, 5, 9, 2, 6, 5];
+  console.log("\nTest 4 - Original:", [...test4]);
+  console.log("Test 4 - Sorted:", selectionSort([...test4]));
+
+  // Test 5: Single element array
+  const test5: number[] = [42];
+  console.log("\nTest 5 - Original:", [...test5]);
+  console.log("Test 5 - Sorted:", selectionSort([...test5]));
+
+  // Test 6: Empty array
+  const test6: number[] = [];
+  console.log("\nTest 6 - Original:", [...test6]);
+  console.log("Test 6 - Sorted:", selectionSort([...test6]));
+
+  // Test 7: Two element array
+  const test7: number[] = [2, 1];
+  console.log("\nTest 7 - Original:", [...test7]);
+  console.log("Test 7 - Sorted:", selectionSort([...test7]));
+
+  // Test 8: Array with negative numbers
+  const test8: number[] = [-5, 2, -3, 8, -1, 0];
+  console.log("\nTest 8 - Original:", [...test8]);
+  console.log("Test 8 - Sorted:", selectionSort([...test8]));
+}
+
+runTests();