java - 在我的合并排序中出现堆栈溢出错误

Question

我在合并排序中遇到堆栈溢出错误。还不确定为什么。

//BAD CODE BAD CODE
public static void main(String[] args) {
    int[] S = {3,4,6,2,5,3,7};
    mergesort(S, 1, 5);
    System.out.println(S);
}   

public static void mergesort(int[] S, int left, int right){
    if (right <= 1) { return; }
    int mid = (right + left) / 2;
    mergesort (S, left, mid);
    mergesort (S, mid+1, right);
    merge(S, left, mid, right); 
}

public static void merge(int[] S, int left, int mid, int right){
    int i, j;
    int[] aux = new int[S.length];

    for (i = mid+1; i > left; i--) {aux[i-1] = S[i-1];}
    for (j = mid; j < right; j++) {aux[right+mid-j] = S[j+1];}
    for (int k = left; k <= right; k++){
        if (aux[j] < aux[i]) {
            S[k] = aux[j--]; 
        } else{
            S[k] = aux[i++];
        }
    }
}
//END OF BAD CODE

更新

感谢您的所有快速回复，我让它正常工作并提出了一些建议的更改。复制粘贴，试一试:

//GOOD CODE
package longest_sequence_proj;
import java.util.*;

public class MergeTest {

/**
 * @param args
 */
public static void main(String[] args) {
    int[] S = {3,4,6,2,5,3,7};

    mergesort(S, 0, 6);

    System.out.println(Arrays.toString(S));

}



public static void mergesort(int[] S, int left, int right){
    if (right <= left) { return; }
    int mid = (right + left) / 2;
    mergesort (S, left, mid);
    mergesort (S, mid+1, right);
    merge(S, left, mid, right);

    }

public static void merge(int[] S, int left, int mid, int right){
    int i, j;
    int[] aux = new int[S.length];

    for (i = mid+1; i > left; i--) {aux[i-1] = S[i-1];}
    for (j = mid; j < right; j++) {aux[right+mid-j] = S[j+1];}
    for (int k = left; k <= right; k++){
        if (aux[j] < aux[i]) {
            S[k] = aux[j--]; 
        } else{
            S[k] = aux[i++];
        }
    }
}
}

Answer 1

你的停止条款是错误的:

 if (right <= 1) { return; }

您实际上想在使用的部分数组的大小 小于 1 时停止，因此您可能正在寻找:

if (right - left <= 1) { return; }

---

作为旁注:

System.out.println(S);

我猜这不是你想要的(它不打印数组，而是对象的标识符...)
为了打印数组使用:

System.out.println(Arrays.toString(S));