[LeetCode] Remove Element

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

用双指针，一个代表当前的长度，另一个往后找和val不相同的

代码

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