leetCode 26.Remove Duplicates from Sorted Array(刪除數組重復點) 解題思路和方法

leetCode 26.Remove Duplicates from Sorted Array(刪除數組重復點) 解題思路和方法

Remove Duplicates from Sorted Array
Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.

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

For example,
Given input array nums = [1,1,2],

Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively. It doesn't matter what you leave beyond the new length.

 

思路：此題比較簡單，大意是將數組中重復點刪除，然後返回新數組的長度。數組中前n個數就是新的數組。唯一難點是不能用額外空間。

詳細代碼如下：

 

public class Solution {
    public int removeDuplicates(int[] nums) {
        if(nums.length <= 1){
            return nums.length;
        }
        int len = 1;//新的長度，至少為1,以下循環從i=1開始
        for(int i = 1; i < nums.length; i++){
            if(nums[i] != nums[i-1]){//不等於前一個元素，長度+1
                nums[len++] = nums[i];//將新的元素裝到前len個
            }
        }
        return len;
    }
}