merge Sort - Java Data Structure

Java examples for Data Structure:Sort

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Description

merge Sort

Demo Code


//package com.java2s;

public class Main {
    public static void mergeSort(Number[] A, int start, int end) {
        if (end - start < 1)
            return;
        int split = ((end - start) / 2) + start;
        mergeSort(A, start, split);/*from   w  w w . j ava2 s  .com*/
        mergeSort(A, split + 1, end);
        merge(A, start, end, split);
    }

    public static void merge(Number[] A, int start, int end, int split) {
        Number[] L = new Number[(split + 1) - start];
        Number[] R = new Number[end - split];

        for (int i = 0; i < L.length; i++) {
            L[i] = A[start + i];
        }
        for (int i = 0; i < R.length; i++) {
            R[i] = A[split + 1 + i];
        }

        int ri = 0;
        int li = 0;

        for (int i = start; i <= end; i++) {

            if (L[li].floatValue() <= R[ri].floatValue()) {
                A[i] = L[li];
                li++;
            } else {
                A[i] = R[ri];
                ri++;
            }
            if (li == L.length) {
                while (ri < R.length) {
                    i++;
                    A[i] = R[ri];
                    ri++;
                }
                return;
            }
            if (ri == R.length) {
                while (li < L.length) {
                    i++;
                    A[i] = L[li];
                    li++;
                }
                return;
            }
        }
    }
}

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