Explanation: The idea is to write the code expressing the basic meaning of
a delete list all elements equal to val
define two nodes: PREV cur and
traverse the entire list:
equal: prve.next cur.next =
cur = cur.next
prev = prev.next
not equal: cur = cur.next
Second, merging two sorted linked
define two nodes result (synthesized new list of the first node) Last (the last node of result)
if cur1.val <= cur2.val
last.next = Cur1
Cur1 = Cur1 .next
otherwise, empathy, update cur2
```class Node {
int val;
Node next = null;
public Node(int val) {
this.val = val;
}
}
public class Solution {
Node removeAll(Node head, int val) {
Node prev = null;
Node cur = head;
while (cur != null) {
if (cur.val == val) {
if (cur == head) {
head = cur.next;
} else {
prev.next = cur.next;
}
} else {
prev = cur;
}
cur = cur.next;
}
return head;
}
Node merge(Node head1, Node head2) {
if (head1 == null) {
return head2;
}
if (head2 == null) {
return head1;
}
Node result = null;
Node last = null;
Node cur1 = head1;
Node cur2 = head2;
while (cur1 != null && cur2 != null) {
if (cur1.val <= cur2.val) {
if (result == null) {
result = cur1;
} else {
last.next = cur1;
}
last = cur1;
cur1 = cur1.next;
} else {
if (result == null) {
result = cur2;
} else {
last.next = cur2;
}
last = cur2;
cur2 = cur2.next;
}
}
if (cur1 != null) {
last.next = cur1;
} else {
last.next = cur2;
}
return result;
}
public static Node createList() {
Node n1 = new Node(6);
Node n3 = new Node(2);
Node n4 = new Node(6);
Node n6 = new Node(4);
Node n8 = new Node(6);
n1.next = n3;
n3.next = n4;
n4.next = n6;
n6.next = n8;
return n1;
}
public static Node createList1() {
Node n1 = new Node(1);
Node n2 = new Node(2);
n1.next = n2;
return n1;
}
public static Node createList2() {
Node n1 = new Node(1);
Node n2 = new Node(3);
Node n3 = new Node(5);
Node n4 = new Node(7);
n1.next = n2;
n2.next = n3;
n3.next = n4;
return n1;
}
public static void main(String[] args) {
Node head = createList();
Node result = new Solution().removeAll(head, 6);
for (Node cur = result; cur != null; cur = cur.next) {
System.out.println(cur.val);
}
System.out.println("=====================");
Node head1 = createList1();
Node head2 = createList2();
Node merged = new Solution().merge(head1, head2);//类中的函数返回值是Node类型,用merge接收
for (Node cur = merged; cur != null; cur = cur.next) {//merge相当于head,代表整个链表
System.out.println(cur.val);
}
}
}