剑指Offer-57

来源：互联网发布：更改4g移动数据dns 编辑：程序博客网时间：2024/05/18 15:27
题目：

在一个排序的链表中，如何删除重复的结点？
实现

public class Solution57 {    public static Node deleteDuplicateNode(Node head){        if (head == null) {            return null;        }//        // 只有一个结点//        if (head.next == null) {//            return head;//        }        // 临时的头结点        Node root = new Node();        root.next = head;        // 记录前驱结点        Node prev = root;        // 记录当前处理的结点        Node cur_node = head;        while (cur_node != null && cur_node.next != null) {            // 有重复结点，与node值相同的结点都要删除            if (cur_node.value == cur_node.next.value) {                // 找到下一个不同值的节点，注意其有可能也是重复节点                while (cur_node.next != null && cur_node.next.value == cur_node.value) {                    cur_node = cur_node.next;                }                // 指向下一个节点，prev.next也可能是重复结点                // 所以prev不要移动到下一个结点                prev.next = cur_node.next;            }            // 相邻两个值不同，说明node不可删除，要保留            else {                prev.next = cur_node;                prev = prev.next;            }            cur_node = cur_node.next;        }        return root.next;    }    public static void main(String[] args) {        test01();        test02();        test03();        test04();        test05();        test06();        test07();        test08();        test09();        test10();    }    // 1->2->3->3->4->4->5    private static void test01() {        Node n1 = new Node(1);        Node n2 = new Node(2);        Node n3 = new Node(3);        Node n4 = new Node(3);        Node n5 = new Node(4);        Node n6 = new Node(4);        Node n7 = new Node(5);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        System.out.println("test1");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->2->3->4->5->6->7    private static void test02() {        Node n1 = new Node(1);        Node n2 = new Node(2);        Node n3 = new Node(3);        Node n4 = new Node(4);        Node n5 = new Node(5);        Node n6 = new Node(6);        Node n7 = new Node(7);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        System.out.println("test2");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->1->1->1->1->1->2    private static void test03() {        Node n1 = new Node(1);        Node n2 = new Node(1);        Node n3 = new Node(1);        Node n4 = new Node(1);        Node n5 = new Node(1);        Node n6 = new Node(1);        Node n7 = new Node(2);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        System.out.println("test3");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->1->1->1->1->1->1    private static void test04() {        Node n1 = new Node(1);        Node n2 = new Node(1);        Node n3 = new Node(1);        Node n4 = new Node(1);        Node n5 = new Node(1);        Node n6 = new Node(1);        Node n7 = new Node(1);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        System.out.println("test4");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->1->2->2->3->3->4->4    private static void test05() {        Node n1 = new Node(1);        Node n2 = new Node(1);        Node n3 = new Node(2);        Node n4 = new Node(2);        Node n5 = new Node(3);        Node n6 = new Node(3);        Node n7 = new Node(4);        Node n8 = new Node(4);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        n7.next = n8;        System.out.println("test5");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->1->2->3->3->4->5->5    private static void test06() {        Node n1 = new Node(1);        Node n2 = new Node(1);        Node n3 = new Node(2);        Node n4 = new Node(3);        Node n5 = new Node(3);        Node n6 = new Node(4);        Node n7 = new Node(5);        Node n8 = new Node(5);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        n7.next = n8;        System.out.println("test6");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->1->2->2->3->3->4->5->5    private static void test07() {        Node n1 = new Node(1);        Node n2 = new Node(1);        Node n3 = new Node(2);        Node n4 = new Node(2);        Node n5 = new Node(3);        Node n6 = new Node(3);        Node n7 = new Node(4);        Node n8 = new Node(5);        Node n9 = new Node(5);        n1.next = n2;        n2.next = n3;        n3.next = n4;        n4.next = n5;        n5.next = n6;        n6.next = n7;        n7.next = n8;        n8.next = n9;        System.out.println("test7");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1->2    private static void test08() {        Node n1 = new Node(1);        Node n2 = new Node(2);        n1.next = n2;        System.out.println("test8");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // 1    private static void test09() {        Node n1 = new Node(1);        System.out.println("test9");        Node result = deleteDuplicateNode(n1);        printListNode(result);    }    // null    private static void test10() {        System.out.println("test10");        Node result = deleteDuplicateNode(null);        printListNode(result);    }    public static void printListNode(Node head){        if(head==null){            System.out.print(" 链表为空");        }        while (head!=null){            System.out.print(" "+head.value);            head = head.next;        }        System.out.print("\n");    }}
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