【问题标题】:How To Split an Array in half in java如何在java中将数组分成两半
【发布时间】:2015-03-05 21:21:42
【问题描述】:

我需要在排序后拆分这个数组,以便打印类似的东西

答:[8, 7, 6, 5]

B: [4, 3, 2, 1]

我知道这可能很简单,但我想不通。我需要做类似 x.length / 2 的事情吗?

 import java.util.Arrays;


public class RecursiveMerge
{

public static void main(String[] args) {
    // TODO Auto-generated method stub
    int [] x= {8,7,5,6,2,4,3,1};
    System.out.println(Arrays.toString(x));
    System.out.println(Arrays.toString(mergeSort(x)));



}

public static int [] mergeSort (int []a)
{
    if(a.length ==1)
        return a;
    else
    {
    int mid =  a.length/2;
    int [] left =mergeSort(Arrays.copyOfRange(a, 0 , mid ));
    int [] right =mergeSort(Arrays.copyOfRange(a, mid, a.length ));

    mergeSort(left);
    mergeSort(right);

    return merge (left, right);
    }
}
public static int[] merge (int[] left, int[] right)
{
int [] result = new int [left.length + right.length];

int leftPtr=0, rightPtr=0, resultPtr=0;


while(leftPtr < left.length && rightPtr < right.length)
    if (left[leftPtr] < right [rightPtr])
        result[resultPtr++] = left[leftPtr++];
    else
        result[resultPtr++] = right[rightPtr++];
while (leftPtr < left.length)
    result[resultPtr++] = left[leftPtr++];
while (rightPtr <right.length)
    result[resultPtr++] = right[rightPtr++];
return result;

}
}

【问题讨论】:

    标签: java arrays sorting


    【解决方案1】:

    要动态制作,根据数组长度做,一分为二:

    int [] x= {8,7,5,6,2,4,3,1};
    int len = x.length;
    
    int a[] = Arrays.copyOfRange(mergeSort(x), 0, len/2);
    int b[] = Arrays.copyOfRange(mergeSort(x), (len/2), len);
    
    System.out.println("A: " + Arrays.toString(a));
    System.out.println("B: " + Arrays.toString(b));
    

    希望对你有帮助。

    【讨论】:

    • 谢谢它,这正是我想要做的
    • 但是,你是要让数组变小吗?因为在方法mergesort(int[] a)中,你是在质疑a.length。
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