203 移除数组元素

203. 移除链表元素 - 力扣（Leetcode）

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//移除链表元素 203
public class RemoveLinkedListElements203 { 
	public static void main(String[] args){
		int[] arr = {3,1,2,3,4,3};
		ListNode head = initLinkedList(arr);
		head = removeElements(head,3);
		printLinkedList(head);
	}

	/**
	 * 虚拟节点方案
	 * @head 链表头节点
	 * @val  删除元素
	 * @return 被删除节点	 
	 */ 
	public static ListNode removeElements(ListNode head, int val) {
        //安全性校验
        if (head == null){
        	return head;
        }
        ListNode dummy = new ListNode(-1,head);
        ListNode pre = dummy;
        ListNode cur = head;

        while(cur != null){
        	if (cur.val == val) {
        		pre.next = cur.next;
        	}else {
        		pre = cur;
        	}
        	cur = cur.next;
        }
        return dummy.next;
    }

    public static ListNode initLinkedList(int[] nums){
    	ListNode head = new ListNode(nums[0]);
    	ListNode pre = head;
    	ListNode cur;
    	for(int i = 1; i < nums.length; i++){
    		cur = new ListNode(nums[i]);
    		pre.next = cur;
 			pre = cur;
    	}
    	return head;
    }

    public static void printLinkedList(ListNode head){
    	ListNode cur = head;
    	while (cur != null){
    		System.out.print(cur.val + " -> ");
    		cur = cur.next;
    	}
    }
}

class ListNode {
	int val;//节点的值
	ListNode next;

	public ListNode (){}

	public ListNode (int val){
		this.val = val;
	} 
	
	public ListNode (int val, ListNode next){
		this.val = val;
		this.next = next;
	}
}