diff --git a/src/hackerrank/interview_preparation_kit/greedy_algorithms/angry_children.js b/src/hackerrank/interview_preparation_kit/greedy_algorithms/angry_children.js
index 14bf0ed1..139b2594 100644
--- a/src/hackerrank/interview_preparation_kit/greedy_algorithms/angry_children.js
+++ b/src/hackerrank/interview_preparation_kit/greedy_algorithms/angry_children.js
@@ -5,7 +5,7 @@
 function maxMin(k, arr) {
   const sortedlist = arr.map((x) => x).sort((a, b) => a - b);
 
-  let result = sortedlist[sortedlist.length - 1] - sortedlist[0];
+  let result = sortedlist.at(-1) - sortedlist[0];
 
   for (let i = 0; i < sortedlist.length - k + 1; i++) {
     const tmin = sortedlist[i];
diff --git a/src/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.js b/src/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.js
index 1665c4ce..c4f64431 100644
--- a/src/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.js
+++ b/src/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.js
@@ -5,7 +5,7 @@
 function minimumAbsoluteDifference(arr) {
   const sortedNums = arr.map((x) => x).sort((a, b) => b - a);
 
-  let result = Math.abs(sortedNums[sortedNums.length - 1] - sortedNums[0]);
+  let result = Math.abs(sortedNums.at(-1) - sortedNums[0]);
 
   for (let i = 0; i < sortedNums.length - 1; i++) {
     const aValue = sortedNums[i];
diff --git a/src/hackerrank/interview_preparation_kit/sort/ctci_comparator_sorting.js b/src/hackerrank/interview_preparation_kit/sort/ctci_comparator_sorting.js
index d0e903f7..257ef823 100644
--- a/src/hackerrank/interview_preparation_kit/sort/ctci_comparator_sorting.js
+++ b/src/hackerrank/interview_preparation_kit/sort/ctci_comparator_sorting.js
@@ -50,4 +50,5 @@ export default {
   comparatorSorting,
   comparatorSortingPrint
 };
-export { Player, SortablePlayer, comparatorSorting, comparatorSortingPrint };
+export { Player } from './ctci_comparator_sorting.Player.js';
+export { SortablePlayer, comparatorSorting, comparatorSortingPrint };
diff --git a/src/hackerrank/interview_preparation_kit/stacks_and_queues/balanced_brackets.js b/src/hackerrank/interview_preparation_kit/stacks_and_queues/balanced_brackets.js
index 6f9bf529..80e46c60 100644
--- a/src/hackerrank/interview_preparation_kit/stacks_and_queues/balanced_brackets.js
+++ b/src/hackerrank/interview_preparation_kit/stacks_and_queues/balanced_brackets.js
@@ -12,10 +12,7 @@ function isBalancedCompute(s) {
   for (const letter of s.split('')) {
     if (letter in pairs) {
       brackets.push(letter);
-    } else if (
-      brackets.length > 0 &&
-      pairs[brackets[brackets.length - 1]] === letter
-    ) {
+    } else if (brackets.length > 0 && pairs[brackets.at(-1)] === letter) {
       brackets.pop();
     } else {
       return false;
diff --git a/src/projecteuler/problem0005.js b/src/projecteuler/problem0005.js
index a722dd9a..688c33d3 100644
--- a/src/projecteuler/problem0005.js
+++ b/src/projecteuler/problem0005.js
@@ -25,7 +25,7 @@ function _replaceMaximum(_element, count, _group) {
   const group = _group;
   if (Object.hasOwn(group, _element)) {
     const elem = _group[_element];
-    group[_element] = count > elem ? count : elem;
+    group[_element] = Math.max(count, elem);
   } else {
     group[_element] = count;
   }
diff --git a/src/projecteuler/problem0007.js b/src/projecteuler/problem0007.js
index fd6b91d9..046d8360 100644
--- a/src/projecteuler/problem0007.js
+++ b/src/projecteuler/problem0007.js
@@ -23,7 +23,7 @@ function problem0007(_top) {
 
   console.log(`primes count: ${primes.length}`);
 
-  const answer = primes[primes.length - 1];
+  const answer = primes.at(-1);
 
   const cycles = i;
   console.log(`${_top} prime number is: ${answer} in ${cycles} cycles`);
diff --git a/src/projecteuler/problem0017.js b/src/projecteuler/problem0017.js
index dd150124..4431e8b0 100644
--- a/src/projecteuler/problem0017.js
+++ b/src/projecteuler/problem0017.js
@@ -12,7 +12,7 @@ function problem0017(init, last) {
 
   for (let i = init; i <= last; i++) {
     word = numberToWord(i);
-    replaced = word.replace(/[^a-z0-9]/gi, '');
+    replaced = word.replaceAll(/[^a-z0-9]/gi, '');
 
     acum += replaced.length;
 
diff --git a/src/projecteuler/problem0018.js b/src/projecteuler/problem0018.js
index bff25afc..f84e3e93 100644
--- a/src/projecteuler/problem0018.js
+++ b/src/projecteuler/problem0018.js
@@ -27,7 +27,7 @@ function problem0018(_triangle) {
   console.debug('leafs count', leafs.length, 'leafs', leafs);
 
   const __START_FROM__ = 0;
-  const max = leafs.reduce((a, b) => (a > b ? a : b), __START_FROM__);
+  const max = leafs.reduce((a, b) => Math.max(a, b), __START_FROM__);
 
   return max;
 }