归并排序 java语言实现

标签：java   归并排序   

package sort;

import java.util.Random;

public class MergeSort {
	
	@SuppressWarnings("unused")
	public boolean initTestArray(int[] testArray) {// 初始化testArray
		if (testArray == null)
			return false;
		Random random = new Random();
		for (int i = 0; i < testArray.length; i++) {
			testArray[i] = random.nextInt(200);
		}
		return true;
	}

	public boolean printTestArray(int[] testArray) {// 打印testArray中的内容
		if (testArray == null)
			return false;
		for (int i = 0; i < testArray.length; i++) {
			System.out.print(testArray[i] + ",");
		}
		System.out.println();
		return true;
	}
	
	public static boolean mergeSort(int[] testArray,int left,int right){
		if(left<right){
			int mid=(left+right)/2;
			mergeSort(testArray,left,mid);
			mergeSort(testArray,mid+1,right);
			if(!merge(testArray,left,mid,right))
				return false;
			//for(int i=0;i<testArray.length;i++)
				//System.out.print(testArray[i]+",");
			//System.out.println();
			return true;
		}
		return true;
	}
	@SuppressWarnings("unused")
	public static boolean merge(int[] testArray,int left,int mid,int right){
		int i=left,j=mid+1,k=0,s=right-left+1;
		int[] testArray2=new int[s];
		if(testArray2==null){
			System.out.println("testArray2存储分配失败！");
			return false;
		}
		while(i<=mid&&j<=right)
			if (testArray[i] <= testArray[j])
				testArray2[k++]=testArray[i++];
			else
				testArray2[k++]=testArray[j++];
			while(i<=mid) testArray2[k++]=testArray[i++];
			while(j<=right) testArray2[k++]=testArray[j++];
			for(i=0;i<s;i++) {
				testArray[left+i]=testArray2[i];
				//System.out.print(testArray2[i]+",");
				}
			//System.out.println();
			
		return true;
	}
	
	public static void main(String args[]){
		int[] testArray = new int[20];
		MergeSort mergeSort=new MergeSort();
		mergeSort.initTestArray(testArray);
		System.out.println("排序前：");
		mergeSort.printTestArray(testArray);
		if(!MergeSort.mergeSort(testArray, 0, testArray.length-1)){
			System.out.println("排序出错！");
			return;
		}
		System.out.println("排序后：");
		mergeSort.printTestArray(testArray);
		
	}

}

归并排序 java语言实现

标签：java   归并排序   

原文地址：http://blog.csdn.net/weiqianghu/article/details/47205699