Add selection sort

Author: benoitvallon

sorting-algorithms-in-javascript/selection-sort-counters.js

@@ -0,0 +1,39 @@
+// sample of arrays to sort
+var arrayRandom = [9, 2, 5, 6, 4, 3, 7, 10, 1, 8];
+var arrayOrdered = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+var arrayReversed = [10, 9, 8, 7, 6, 5, 4, 3, 2, 1];
+
+// swap function helper
+function swap(array, i, j) {
+  var temp = array[i];
+  array[i] = array[j];
+  array[j] = temp;
+}
+
+function selectionSort(array) {
+  var countOuter = 0;
+  var countInner = 0;
+  var countSwap = 0;
+
+  for(var i = 0; i < array.length; i++) {
+    countOuter++;
+    var min = i;
+    for(var j = i + 1; j < array.length; j++) {
+      countInner++;
+      if(array[j] < array[min]) {
+        min = j;
+      }
+    }
+    if(i !== min) {
+      countSwap++;
+      swap(array, i, min);
+    }
+  }
+
+  console.log('outer:', countOuter, 'inner:', countInner, 'swap:', countSwap);
+  return array;
+}
+
+selectionSort(arrayRandom.slice()); // => outer: 10 inner: 45 swap: 5
+selectionSort(arrayOrdered.slice()); // => outer: 10 inner: 45 swap: 0
+selectionSort(arrayReversed.slice()); // => outer: 10 inner: 45 swap: 5

sorting-algorithms-in-javascript/selection-sort.js

@@ -0,0 +1,26 @@
+// array to sort
+var array = [9, 2, 5, 6, 4, 3, 7, 10, 1, 8];
+
+// swap function helper
+function swap(array, i, j) {
+  var temp = array[i];
+  array[i] = array[j];
+  array[j] = temp;
+}
+
+function selectionSort(array) {
+  for(var i = 0; i < array.length; i++) {
+    var min = i;
+    for(var j = i + 1; j < array.length; j++) {
+      if(array[j] < array[min]) {
+        min = j;
+      }
+    }
+    if(i !== min) {
+      swap(array, i, min);
+    }
+  }
+  return array;
+}
+
+console.log(selectionSort(array)); // => [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]