leetcode27. Remove Element

最新推荐文章于 2025-12-15 23:25:39 发布

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本文介绍了一种在不使用额外数组的情况下，从数组中移除指定值并返回新长度的算法实现。通过遍历数组并将非目标值元素向前移动来完成任务，确保了常数级别的空间复杂度。

Remove Element
Given an array and a value, remove all instances of that value in place and return the new length.

Do not allocate extra space for another array, you must do this in place with constant memory.

The order of elements can be changed. It doesn’t matter what you leave beyond the new length.

Example:
Given input array nums = [3,2,2,3], val = 3

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

解法

遇到target跳过。

public class Solution {
    public int removeElement(int[] nums, int val) {
        if (nums == null || nums.length == 0) {
            return 0;
        }

        int count = 0;
        for (int i = 0; i < nums.length; i++) {
            if (nums[i] != val) {
                nums[count++] = nums[i];
            }
        }

        return count; 
    }
}