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：
设置一个临时变量j，从头遍历数组，如果nums[i]不等于3，则修改nums[j]的值，并将j加1。

Java代码：

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