Java从双向链表中查找最大值和最小值节点
在此程序中，我们将创建双向链接列表，然后遍历该列表以找出最小和最大节点。
我们将维护两个变量min和max。最小值将保留最小值节点，最大值将保留最大值节点。在上面的示例中，1将是最小值节点，9将是最大值节点。
算法
定义一个代表列表中节点的Node类。它将具有三个属性: 数据，前一个将指向上一个节点，下一个将指向下一个节点。
定义另一个用于创建双向链表的类，它有两个节点: head和tail。最初，头和尾将指向null。
minimumNode()将打印出最小值节点: 定义变量min并使用head的数据进行初始化。 电流将指向头部。 通过比较每个节点的数据和最小值来遍历列表。 如果min>当前数据，则min将保存当前数据。 在列表的末尾，变量min将保存最小值节点。 打印最小值。
a.maximumNode()将打印出最大值节点:
定义变量max并使用head的数据进行初始化。
电流将指向头部。
通过比较每个节点的数据与最大值来遍历列表。
如果max
<当前数据，则max将保存当前数据。< span>
在列表的末尾，变量max将保存最大值节点。
打印最大值。
程序:
public class MinMax {
//Represent a node of the doubly linked list
class Node{
int data;
Node previous;
Node next;
public Node(int data) {
this.data = data;
}
}
//Represent the head and tail of the doubly linked list
Node head, tail = null;
//addNode() will add a node to the list
public void addNode(int data) {
//Create a new node
Node newNode = new Node(data);
//if list is empty
if(head == null) {
//Both head and tail will point to newNode
head = tail = newNode;
//head's previous will point to null
head.previous = null;
//tail's next will point to null, as it is the last node of the list
tail.next = null;
}
else {
//newNode will be added after tail such that tail's next will point to newNode
tail.next = newNode;
//newNode's previous will point to tail
newNode.previous = tail;
//newNode will become new tail
tail = newNode;
//As it is last node, tail's next will point to null
tail.next = null;
}
}
//MinimumNode() will find out minimum value node in the list
public int minimumNode() {
//Node current will point to head
Node current = head;
int min;
//Checks if list is empty
if(head == null) {
System.out.println("List is empty");
return 0;
}
else {
//Initially, min will store the value of head's data
min = head.data;
while(current != null) {
//if the value of min is greater than the current's data
//Then, replace the value of min with current node's data
if(min > current.data)
min = current.data;
current = current.next;
}
}
return min;
}
//MaximumNode() will find out maximum value node in the list
public int maximumNode() {
//Node current will point to head
Node current = head;
int max;
//Checks if list is empty
if(head == null) {
System.out.println("List is empty");
return 0;
}
else {
//Initially, max will store the value of head's data
max = head.data;
//if value of max is lesser than current's data
//Then, replace value of max with current nodes data
while(current != null) {
if(current.data > max)
max = current.data;
current = current.next;
}
}
return max;
}
public static void main(String[] args) {
MinMax dList = new MinMax();
//Add nodes to the list
dList.addNode(5);
dList.addNode(7);
dList.addNode(9);
dList.addNode(1);
dList.addNode(2);
//Prints the minimum value node in the list
System.out.println("Minimum value node in the list: "+ dList.minimumNode());
//Prints the maximum value node in the list
System.out.println("Maximum value node in the list: "+ dList.maximumNode());
}
}
输出:
Minimum value node in the list: 1
Maximum value node in the list: 9
