Remove Duplicate Numbers in Array

最新推荐文章于 2025-02-03 15:37:10 发布

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最新推荐文章于 2025-02-03 15:37:10 发布

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分类专栏： Two pointers

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本文介绍了一种使用双指针技术在原地修改输入数组以移除重复元素的方法，并确保每个元素只出现一次。该方法不使用额外空间，仅通过修改输入数组实现，符合O(1)额外内存的要求。

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Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length.

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

Example 1:

Given nums = [1,1,2],

Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively.

It doesn't matter what you leave beyond the returned length.

You don't need to keep the original order of the integers.

思路:双指针，每次把i ！= j的值，赋值到++i的位子，最后返回i+1，因为是个数；

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