Add bubble sort

Author: benoitvallon

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

@@ -0,0 +1,64 @@
+// 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;
+}
+
+// be careful: this is a very basic implementation which is nice to understand the deep principle of bubble sort (going through all comparisons) but it can be greatly improved for performances
+function bubbleSortBasic(array) {
+  var countOuter = 0;
+  var countInner = 0;
+  var countSwap = 0;
+
+  for(var i = 0; i < array.length; i++) {
+    countOuter++;
+    for(var j = 1; j < array.length; j++) {
+      countInner++;
+      if(array[j - 1] > array[j]) {
+        countSwap++;
+        swap(array, j - 1, j);
+      }
+    }
+  }
+
+  console.log('outer:', countOuter, 'inner:', countInner, 'swap:', countSwap);
+  return array;
+}
+
+bubbleSortBasic(arrayRandom.slice()); // => outer: 10 inner: 90 swap: 21
+bubbleSortBasic(arrayOrdered.slice()); // => outer: 10 inner: 90 swap: 0
+bubbleSortBasic(arrayReversed.slice()); // => outer: 10 inner: 90 swap: 45
+
+// correct implementation: this is the usual implementation of the bubble sort algorithm. Some loops execution are avoided if not they are not needed
+function bubbleSort(array) {
+  var countOuter = 0;
+  var countInner = 0;
+  var countSwap = 0;
+
+  var swapped;
+  do {
+    countOuter++;
+    swapped = false;
+    for(var i = 0; i < array.length; i++) {
+      countInner++;
+      if(array[i] && array[i + 1] && array[i] > array[i + 1]) {
+        countSwap++;
+        swap(array, i, i + 1);
+        swapped = true;
+      }
+    }
+  } while(swapped);
+
+  console.log('outer:', countOuter, 'inner:', countInner, 'swap:', countSwap);
+  return array;
+}
+
+bubbleSort(arrayRandom.slice()); // => outer: 9 inner: 90 swap: 21
+bubbleSort(arrayOrdered.slice()); // => outer: 1 inner: 10 swap: 0
+bubbleSort(arrayReversed.slice()); // => outer: 10 inner: 100 swap: 45

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

@@ -0,0 +1,40 @@
+// 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;
+}
+
+// be careful: this is a very basic implementation which is nice to understand the deep principle of bubble sort (going through all comparisons) but it can be greatly improved for performances
+function bubbleSortBasic(array) {
+  for(var i = 0; i < array.length; i++) {
+    for(var j = 1; j < array.length; j++) {
+      if(array[j - 1] > array[j]) {
+        swap(array, j - 1, j);
+      }
+    }
+  }
+  return array;
+}
+
+console.log(bubbleSortBasic(array.slice())); // => [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
+
+// correct implementation: this is the usual implementation of the bubble sort algorithm. Some loops execution are avoided if not they are not needed
+function bubbleSort(array) {
+  var swapped;
+  do {
+    swapped = false;
+    for(var i = 0; i < array.length; i++) {
+      if(array[i] && array[i + 1] && array[i] > array[i + 1]) {
+        swap(array, i, i + 1);
+        swapped = true;
+      }
+    }
+  } while(swapped);
+  return array;
+}
+
+console.log(bubbleSort(array.slice())); // => [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]