順序表
- 數據保存在連續的內存空間上
- 支持隨機訪問
- 擅長尾插和尾刪(O(1),如若觸發擴容邏輯 - > O(N)
- 不擅長中間位置插入/刪除 O(N) ,效率低
public class SeqList {
private int[] datas = new int[100];
private int size = 0;
public int getSize() {
return size;
}
public void display() {
String ret = "[";
for (int i = 0; i < size; i++) {
ret += datas[i];
if(i < size - 1){
ret += ",";
}
}
ret += "]";
System.out.println(ret);
}
public void add(int pos, int data) {
if(pos < 0 || pos > size){
return;
}
if(size >= datas.length){
int[] newDatas = new int[datas.length * 2];
for (int i = 0; i < datas.length ; i++) {
newDatas[i] = datas[i];
}
datas = newDatas;
}
if(pos == size){
datas[pos] = data;
size++;
return;
}
for (int i = size - 1;i >= pos;i--) {
datas[i + 1] = datas[i];
}
datas[pos] = data;
size++;
}
public boolean contains(int toFind) {
for (int i = 0; i < size; i++) {
if (datas[i] == toFind) {
return true;
}
}
return false;
}
public int search(int toFind) {
for (int i = 0; i < size; i++) {
if(datas[i] == toFind){
return i;
}
}
return -1;
}
public int getPos(int pos) {
return datas[pos];
}
public void setPos(int pos, int value) {
datas[pos] = value;
}
public void remove(int toRemove) {
int pos = search(toRemove);
if(pos == -1) {
return;
}
if(pos == size - 1){
size--;
return;
}
for(int i = pos;i < size - 1; i++) {
datas[i] = datas[i + 1];
}
size--;
}
public void clear() {
size = 0;
}
}
鏈表
- 元素之間不是在連續的內存空間上,給每個數據節點引入了一個next引用,通過這個引用就能找到當前節點的下一個節點
- 不支持隨機訪問
- 擅長中間插入元素/刪除元素 O(1),效率高
- 存儲相同數量的數據時,鏈表佔用的內存空間比順序表大(因爲鏈表的每個節點還得維護一個next)
class Node {
public int data;
public Node next = null;
public Node(int data) {
this.data = data;
}
}
public class LinkedList {
private Node head = null;
public void display() {
for(Node cur = head; cur != null; cur = cur.next) {
System.out.print(cur.data + " ");
}
System.out.println();
}
public void addFirst(int data) {
Node node = new Node(data);
if (head == null) {
head = node;
return;
}
node.next = head;
head = node;
}
public void addLast(int data) {
Node node = new Node(data);
if(head == null) {
head = node;
return;
}
Node tail = head;
while(tail.next != null) {
tail = tail.next;
}
tail.next = node;
node.next = null;
}
private int getSize() {
int size = 0;
for (Node cur = head; cur != null; cur = cur.next){
size++;
}
return size;
}
public boolean addIndex(int index,int data) {
int size = getSize();
if (index < 0 || index > size) {
return false;
}
if (index == 0) {
addFirst(data);
return true;
}
if (index == size) {
addLast(data);
return true;
}
Node node = new Node(data);
Node prev = getPos(index - 1);
node.next = prev.next;
prev.next = node;
return true;
}
private Node getPos(int index) {
Node cur = head;
for (int i = 0; i < index; i++) {
cur = cur.next;
}
return cur;
}
public boolean contain(int key) {
for (Node cur = head; cur != null;cur = cur.next) {
if (cur.data == key) {
return true;
}
}
return false;
}
public void remove(int key) {
if (head.data == key) {
head = head.next;
return;
}
Node prev = searchPrev(key);
Node toDelete = prev.next;
prev.next = toDelete.next;
}
private Node searchPrev(int key) {
for (Node cur = head; cur != null
&& cur.next != null;cur = cur.next) {
if (cur.next.data == key) {
return cur;
}
}
return null;
}
public void removeAll(int key) {
Node prev = head;
Node cur = head.next;
while (cur != null) {
if (cur.data == key) {
prev.next = cur.next;
cur = prev.next;
}else {
prev = cur;
cur = cur.next;
}
}
if (head.data == key) {
head = head.next;
}
}
public void clear() {
head = null;
}
}