Question

我坚持使用这种合并排序方法。我不是试图递归地做，但我不能让这个为我工作。我认为需要做一些微小的改变才能让它发挥作用。有什么建议？

  protected static void merge(long[] a, long[] workSpace, int lowPtr, int highPtr, int upperBound) {
    int j = 0;                             // workspace index
    int lowerBound = lowPtr;
    int mid = highPtr-1;
    int n = upperBound-lowerBound+1;       // # of items

    while(lowPtr <= mid && highPtr <= upperBound)
        if(a[lowPtr] < a[highPtr] )
            workSpace[j++] = a[lowPtr++];
        else
            workSpace[j++] = a[highPtr++];

    while(lowPtr <= mid)
        workSpace[j++] = a[lowPtr++];

    while(highPtr <= upperBound)
        workSpace[j++] = a[highPtr++];

    for(j=0; j<n; j++)
        a[lowerBound+j] = workSpace[j];

Answer 1

我怀疑它与你如何在外部使用这个例程有关。我在5分钟后盯着它看不到错误，所以我测试了它似乎工作正常。

你不需要知道c ++（这就是我碰巧在这台机器上有一个方便的编译器）

int main() {
    long a[10] = {1,2,3,4,15,5,11,12,13,14}; // two sorted halves to merge
    long * temp = new long[10];
    for (int i = 0; i < 10; i++)
    {
        cout << a[i] << ","; // printout before merge
    }
    cout << endl;
    merge(a, temp, 0, 5, 9); // 0-4 and 5-9
    for (int i = 0; i < 10; i++)
    {
        cout << a[i] << ","; // printout after merge
    }
}

输出：

1,2,3,4,15,5,11,12,13,14,
1,2,3,4,5,11,12,13,14,15,

更多的输出只是为了说服你：

1,2,6,14,15,5,11,12,32,100,
1,2,5,6,11,12,14,15,32,100,

1,2,100,143,1500,5,112,121,320,1000,
1,2,5,100,112,121,143,320,1000,1500,

12,20,100,143,179,5,12,121,320,430,
5,12,12,20,100,121,143,179,320,430,

迭代合并排序无法正常工作

1 个答案: