27. 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.

思路:又是两指针。一个用来遍历,一个用来记录满足要求的值。
类似题目: Leetcode 26, 382

public class Solution {
    public int removeElement(int[] nums, int val) {
        if (nums == null || nums.length == 0) return 0;
        int newidx = 0;
        int i = 0;
        while(i < nums.length) {
            if (nums[i] != val) {
                nums[newidx] = nums[i];
                newidx++;
            }
            i++;
        }
        return newidx;

    }
}
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