[BUGFIX] sonarqube: Prefer .at(…) over [….length - index].

Complex index access patterns should be replaced with ".at()" method typescript:S7755

Author: Gonzalo Diaz

src/hackerrank/interview_preparation_kit/greedy_algorithms/angry_children.ts

@@ -7,7 +7,7 @@ function maxMin(k: number, arr: number[]): number {
     .map((x: number): number => x)
     .sort((a: number, b: number): number => a - b);
 
-  let result = sortedlist[sortedlist.length - 1] - sortedlist[0];
+  let result = (sortedlist.at(-1) ?? 0) - sortedlist[0];
 
   for (let i = 0; i < sortedlist.length - k + 1; i++) {
     const tmin = sortedlist[i];

src/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.ts

@@ -7,7 +7,7 @@ function minimumAbsoluteDifference(arr: number[]): number {
     .map((x: number): number => x)
     .sort((a: number, b: number): number => b - a);
 
-  let result = Math.abs(sortedNums[sortedNums.length - 1] - sortedNums[0]);
+  let result = Math.abs((sortedNums.at(-1) ?? 0) - sortedNums[0]);
 
   for (let i = 0; i < sortedNums.length - 1; i++) {
     const aValue = sortedNums[i];