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Adding merge sort practice code

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hitanshu310 2025-02-04 02:28:31 +05:30 committed by hitanshu
parent 05db13b2ee
commit d6d3111f51
1 changed files with 0 additions and 33 deletions
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module6/src/main/java/com/hithomelabs/princeton1/module6/Merge.java
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@ -7,39 +7,6 @@ import java.util.Arrays;
public class Merge<E> extends AbstractCustomSorts<E> { public class Merge<E> extends AbstractCustomSorts<E> {
@Override @Override
public void sort(E[] arr) { public void sort(E[] arr) {
int N = arr.length;
// * * aux is a helper array required for merge
E[] aux = Arrays.copyOf(arr, N);
mergesort(arr, aux, 0, N-1);
}
private void mergesort(E[] arr, E[] aux, int lo, int hi) {
if (hi <= lo) return;
int mid = lo + (hi - lo)/2;
mergesort(arr, aux, lo, mid);
mergesort(arr, aux, mid+1, hi);
merge(arr, aux, lo, mid, hi);
}
private void merge(E[] arr, E[] aux, int lo, int mid, int hi) {
// * * creating backup of original array
for (int i = lo; i <= hi; i++)
aux[i] = arr[i];
int i = lo;
int j = mid+1;
for (int k = lo; k <= hi; k++){
// * If i has already reached mid, no need to compare we insert at pointer k
if(i > mid) arr[k] = aux[j++];
else if(j > hi) arr[k] = aux[i++];
else if(less((Comparable<E>) aux[i], aux[j])) arr[k] = aux[i++];
else arr[k] = aux[j++];
}
} }
} }