[英]Sorting String Array Indicies with Insertion Sort, Doubly Linked List
我正在做一個作業,在該作業中,我必須對數組進行排序並將索引存儲在已構建的雙向鏈接列表ADT中。
Example:
{"A","B","C","A"} -> {0,3,1,2}
我當前的方法是將索引放入ADT中,然后在對數組進行排序時對ADT進行排序。 據我所知,每次循環執行時,我都會在數組和雙向鏈表上執行完全相同的操作,但是我的輸出不匹配。
public static void main(String[] args ) {
List A = new List();
String[] inputArray = {"A","C","B","A"};
int i,j;
String key;
//load indices into doubly-linked list
for (int x = 0; x < inputArray.length; x++ ) {
A.append(x);
}
//begin insertion sort
for (j = 1; j < inputArray.length; j++) {
System.out.println(A);
System.out.println(Arrays.toString(inputArray));
key = inputArray[j];
i = j - 1;
while (i >= 0) {
if (key.compareTo(inputArray[i]) > 0) {
break;
}
inputArray[i+1] = inputArray[i];
//moveTo moves the cursor to <int>
A.moveTo(i);
//make sure we aren't trying to insert before first node
if (i > 0) { A.insertBefore(i+1); }
else { A.prepend(i+1); }
//remove node at cursor
A.delete();
i--;
}
inputArray[i+1] = key;
A.moveTo(i+1);
if (i > 0) { A.insertBefore(i+1); }
else { A.prepend(i+1); }
A.delete();
}
System.out.println(A);
System.out.println(Arrays.toString(inputArray));
}
上面的代碼提供以下輸出:
跑:
0 1 2 3
[A,C,B,A]
1 0 2 3
[A,C,B,A]
1 1 2 3
[A,B,C,A]
0 2 3 3
[A,A,B,C]
建立成功(總時間:0秒)
編輯:List.java
public class List {
private class Node{
//Fields
int data;
Node next, previous;
//Constructor
Node(int data) {
this.data = data;
next = null;
previous = null;
}
public String toString() { return String.valueOf(data); }
}
//Fields
private Node frontNode, backNode, cursorNode;
private int totalSize, cursorPosition;
//Constructor
List() {
frontNode = backNode = cursorNode = null;
totalSize = 0;
cursorPosition = -1;
}
//moveTo(int i): If 0<=i<=length()-1, moves the cursor to the element
// at index i, otherwise the cursor becomes undefined.
void moveTo(int i) {
if (i == 0) {
cursorPosition = i;
cursorNode = frontNode;
}
else if (i == length() - 1) {
cursorPosition = i;
cursorNode = backNode;
}
else if (i > 0 && i < length() - 1 ) {
cursorNode = frontNode;
cursorPosition = i;
for (int x=0; x < i; x++) {
cursorNode = cursorNode.next;
}
}
else {
cursorPosition = -1;
}
}
//prepend(int data): Inserts new element before front element in this List.
void prepend(int data) {
Node node = new Node(data);
if ( this.length() == 0 ) {
frontNode = backNode = node;
}
else {
frontNode.previous = node;
node.next = frontNode;
frontNode = node;
}
totalSize++;
//cursorPosition might change?
}
//insertBefore(int data): Inserts new element before cursor element in this
// List. Pre: length()>0, getIndex()>=0
void insertBefore(int data) {
Node node = new Node(data);
if ( this.length() > 0 && this.getIndex() >= 0 ) {
node.previous = cursorNode.previous;
node.next = cursorNode;
cursorNode.previous.next = node;
cursorNode.previous = node;
totalSize++;
}
else if ( this.length() <= 0 )
{
throw new RuntimeException
("Error: insertBefore called on empty list");
}
else {
throw new RuntimeException
("Error: insertBefore called without cursor set");
}
}
好,謝謝。 我不確切知道打算要執行insertBefore()和prepend()(我可能已經猜到了,但是編程不應該是猜測應該做什么方法;看文檔會更好)。
由於這是一項任務,因此我不會給您答案。 但是線索是這樣的:在第一次通過循環之后,A的轉儲會為您提供與開始時相同的索引,但是會重新排列。 我認為這就是每次循環迭代后的方式。 但這在第二次通過循環之后是不正確的(1出現兩次,而0消失了)。 想一想。 當你打電話A.insertBefore()來重新排列的元素,什么樣的數據,你應該告訴的insertBefore()來插入,是什么?你居然插入?
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