LeetCode-Easy刷題(8) 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 by modifying the input array in-place with O(1) extra memory.

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

Example:

Given nums = [3,2,2,3], val = 3,

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

給定一個數組和一個值，刪除該值的所有實例並返回新的長度。 不要爲另一個數組分配額外的空間，您必須通過修改帶有O(1)額外內存的輸入數組來實現這一點。 元素的順序可以被改變。你在新的長度之外留下什麼並不重要。

這題和上題類似通過控制數組的雙指針來完成:

    public static int removeElement(int[] nums, int val) {

        if(nums ==null || nums.length<1){
            return 0;
        }
        int index = 0;
        for (int i = 0; i < nums.length; i++) {
            if(nums[i]!=val){
                nums[index] = nums[i];
                index++;
            }
        }
        return index;
    }