From 376f60ddc6a4a39dc2720727766a70feade8a88d Mon Sep 17 00:00:00 2001 From: Mandy8055 Date: Fri, 6 Aug 2021 22:54:48 +0530 Subject: [PATCH 1/4] Added the correct and stable version of count sort. Changed function declaration to ES6 style. --- Sorts/CountingSort.js | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/Sorts/CountingSort.js b/Sorts/CountingSort.js index 2003cfb73..01bfc2b7e 100644 --- a/Sorts/CountingSort.js +++ b/Sorts/CountingSort.js @@ -8,31 +8,38 @@ * Animated Visual: https://www.cs.usfca.edu/~galles/visualization/CountingSort.html */ -function countingSort (arr, min, max) { - let i - let z = 0 +const countingSort = (arr, min, max) => { + // Create an auxiliary resultant array + const res = [] + // Create the freq array const count = [] + let len = max - min + 1 - for (i = min; i <= max; i++) { + for (let i = 0; i < len; i++) { count[i] = 0 } - - for (i = 0; i < arr.length; i++) { - count[arr[i]]++ + // Populate the freq array + for (let i = 0; i < arr.length; i++) { + count[arr[i] - min] += 1 } - - for (i = min; i <= max; i++) { - while (count[i]-- > 0) { - arr[z++] = i - } + // Create a prefix sum array out of the freq array + count[0] -= 1 + for (let i = 1; i < count.length; i++) { + count[i] += count[i - 1] } - + // Populate the result array using the prefix sum array + for (let i = arr.length - 1; i >= 0; i--) { + res[count[arr[i] - min]] = arr[i] + count[arr[i] - min]-- + } + // Copy the result back to back to original array + arr = [...res] return arr } /** -* Implementation of Counting Sort -*/ + * Implementation of Counting Sort + */ const array = [3, 0, 2, 5, 4, 1] // Before Sort console.log('\n- Before Sort | Implementation of Counting Sort -') From c55ca93584e7e00b34c8ee3c4d5ebab76a6acec5 Mon Sep 17 00:00:00 2001 From: Mandy8055 Date: Sun, 8 Aug 2021 16:42:13 +0530 Subject: [PATCH 2/4] Updated the count sort algorithm with stable implementation. Added ES6 syntactic sugar to the syntax --- Sorts/CountingSort.js | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/Sorts/CountingSort.js b/Sorts/CountingSort.js index 01bfc2b7e..cc2dd18e5 100644 --- a/Sorts/CountingSort.js +++ b/Sorts/CountingSort.js @@ -12,12 +12,8 @@ const countingSort = (arr, min, max) => { // Create an auxiliary resultant array const res = [] // Create the freq array - const count = [] let len = max - min + 1 - - for (let i = 0; i < len; i++) { - count[i] = 0 - } + const count = new Array(len).fill(0) // Populate the freq array for (let i = 0; i < arr.length; i++) { count[arr[i] - min] += 1 From 6232f8dd42f2d5f001f7715c0e1f1a24ce9dbc32 Mon Sep 17 00:00:00 2001 From: Mandy8055 Date: Sun, 8 Aug 2021 17:14:41 +0530 Subject: [PATCH 3/4] Updated the count sort algorithm with stable implementation. Added ES6 syntactic sugar to the syntax --- Sorts/CountingSort.js | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/Sorts/CountingSort.js b/Sorts/CountingSort.js index cc2dd18e5..86389b720 100644 --- a/Sorts/CountingSort.js +++ b/Sorts/CountingSort.js @@ -28,9 +28,7 @@ const countingSort = (arr, min, max) => { res[count[arr[i] - min]] = arr[i] count[arr[i] - min]-- } - // Copy the result back to back to original array - arr = [...res] - return arr + return res } /** From faed847317aae6ed061200377741538f30f38371 Mon Sep 17 00:00:00 2001 From: Mandy8055 Date: Sun, 8 Aug 2021 17:21:05 +0530 Subject: [PATCH 4/4] Updated the count sort algorithm with stable implementation. Added ES6 syntactic sugar to the syntax. Removed the unwanted len variable and updated the comments --- Sorts/CountingSort.js | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/Sorts/CountingSort.js b/Sorts/CountingSort.js index 86389b720..a31ea4455 100644 --- a/Sorts/CountingSort.js +++ b/Sorts/CountingSort.js @@ -11,14 +11,13 @@ const countingSort = (arr, min, max) => { // Create an auxiliary resultant array const res = [] - // Create the freq array - let len = max - min + 1 - const count = new Array(len).fill(0) + // Create and initialize the frequency[count] array + const count = new Array(max - min + 1).fill(0) // Populate the freq array for (let i = 0; i < arr.length; i++) { - count[arr[i] - min] += 1 + count[arr[i] - min]++ } - // Create a prefix sum array out of the freq array + // Create a prefix sum array out of the frequency[count] array count[0] -= 1 for (let i = 1; i < count.length; i++) { count[i] += count[i - 1]