fix pivot picking and kruskal's algorithm

Author: larskotthoff

src/algorithms/graph/kruskal/kruskal.js

@@ -24,7 +24,7 @@ export default function kruskal(graph){
  */
 compareCallback: (graphEdgeA,graphEdgeB)=>{
 if(graphEdgeA.weight===graphEdgeB.weight){
-return1;
+return0;
 }
 
 returngraphEdgeA.weight<=graphEdgeB.weight ? -1 : 1;

src/algorithms/sorting/quick-sort/QuickSort.js

@@ -22,11 +22,15 @@ export default class QuickSort extends Sort{
 // Take the median element of first, mid, and last elements.
 letpivotElement=array[0];
 constmid=Math.floor(array.length/2);
-if((array[mid]<array[array.length-1]&&array[mid]>array[0])
-||(array[mid]>array[array.length-1]&&array[mid]<array[0])){
+if((this.comparator.lessThan(array[mid],array[array.length-1])
+&&this.comparator.greaterThan(array[mid],array[0]))
+||(this.comparator.greaterThan(array[mid],array[array.length-1])
+&&this.comparator.lessThan(array[mid],array[0]))){
 pivotElement=array[mid];
-}elseif((array[array.length-1]<array[mid]&&array[array.length-1]>array[0])
-||(array[array.length-1]>array[mid]&&array[array.length-1]<array[0])){
+}elseif((this.comparator.lessThan(array[array.length-1],array[mid])
+&&this.comparator.greaterThan(array[array.length-1],array[0]))
+||(this.comparator.greaterThan(array[array.length-1],array[mid])
+&&this.comparator.lessThan(array[array.length-1],array[0]))){
 pivotElement=array[array.length-1];
 }