[LeetCode]Remove Duplicates from Sorted Array

题目：Remove Duplicates from Sorted Array

删除数组中重复元素。

public class Solution {
    public int removeDuplicates(int[] nums) {
        int i = 0,j = 1;
        while(j < nums.length){
            if(nums[j] != nums[j - 1]){
                nums[i++] = nums[j - 1];
                if(j == nums.length - 1)nums[i++] = nums[j];
            }else if(j == nums.length - 1){
                nums[i++] = nums[j];
            }
            j++;
        }
        if(nums.length == 1)return 1;
        return i;
    }
}

题目：Remove Duplicates from Sorted ArrayII

保证数组中同一元素重复次数不超过2次。

public class Solution {
    public int removeDuplicates(int[] nums) {
        if(nums.length == 1)return 1;
        int count = 0,i = 0,j = 1;
        while(j < nums.length){
            if(nums[j - 1] == nums[j]){
                count++;
            }else{
                if(count >= 1){
                    nums[i++] = nums[j - 2];
                    count = 0;
                }
                nums[i++] = nums[j - 1];
            }
            if(j == nums.length - 1){
                if(nums[j - 1] == nums[j])nums[i++] = nums[j - 1];
                nums[i++] = nums[j];
            }
            j++;
        }
        return i;
    }
}

题目：Remove Duplicates from Sorted List II

删除已序链表中的重复元素。

package com.example.medium;

/**
 * Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
 * For example,
 * Given 1->2->3->3->4->4->5, return 1->2->5.
 * Given 1->1->1->2->3, return 2->3.
 * @author FuPing
 *
 */
public class DeleteDuplicates {
    public class ListNode {
        int val;
        ListNode next;
        ListNode(int x) { val = x; }
    }
    public ListNode deleteDuplicates(ListNode head) {
        if(head == null || head.next == null)return head;//头为空
        ListNode p = head.next,pre = head;
        boolean flag = false,headFlag = false;
        if(pre.val == p.val)headFlag = true;//头元素是否重复
        while(p.next != null){
            if(p.val == p.next.val){
                p.next = p.next.next;
                flag = true;
            }else{
                if(flag){//有重复元素
                    pre.next = p.next;
                    flag = false;
                }else{
                    pre = pre.next;
                }
                p = p.next;
            }
        }
        if(flag)pre.next = p.next;
        if(headFlag){//删除头部
            if(head.next != null && head.val == head.next.val)
                return head.next.next;
            return head.next;
        }
        return head;
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

}