Java List Sort mergeSort(List list)

Description

MergeSorts the given list.

License

Apache License

Declaration

public static <K extends Comparable<K>> List<K> mergeSort(List<K> list) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.util.ArrayList;
import java.util.List;

public class Main {
    /**/* w  w w.j  a  v  a2s.com*/
     * MergeSorts the given list.
     */
    public static <K extends Comparable<K>> List<K> mergeSort(List<K> list) {
        if (list.size() <= 1) {
            return list;
        } else {
            int half = list.size() / 2;
            List<K> left = mergeSort(subList(list, 0, half - 1));
            List<K> right = mergeSort(subList(list, half, list.size() - 1));
            return merge(left, right);
        }
    }

    /**
     * Sublists the given list.
     */
    public static <K> List<K> subList(List<K> list, int begin, int end) {
        List<K> temp = new ArrayList<>(end - begin);
        for (int i = begin; i <= end; i++) {
            temp.add(list.get(i));
        }
        return temp;
    }

    /**
     * Merges two sorted segments into a single sorted list.
     */
    public static <K extends Comparable<K>> List<K> merge(List<K> list1, List<K> list2) {
        List<K> newList = new ArrayList<>(list1.size() + list2.size());

        int offset1 = 0;
        int offset2 = 0;

        while (!list1.isEmpty() && !list2.isEmpty()) {
            K item1 = list1.get(offset1);
            K item2 = list2.get(offset2);
            if (item1.compareTo(item2) <= 0) {
                newList.add(item1);
                list1.remove(offset1);
            } else {
                newList.add(item2);
                list2.remove(offset2);
            }

            if (offset1 == list1.size()) {
                newList.addAll(list2);
            }
            if (offset2 == list2.size()) {
                newList.addAll(list1);
            }
        }

        return newList;
    }
}

Related

1. ListToSortedArray(List list)
2. mapTosortedScoreList(HashMap unSortedMap)
3. maximum(List sortedDataAscendingOrder)
4. mergeLong(List l1, List l2, boolean sort)
5. mergeSort(List m)
6. mergeSortedLists(List dest, List[] src, boolean removeDuplicates)
7. quickSort(Comparable[] list, int min, int max)
8. removeSortByColumnName(List sortProperty, List ascending, String columnName)
9. removeSortColumns(List selectColumns, List sorts, List ascending)