Leetcode 26 - 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.

1 - 注意题目要求使用constant memory，因此不能再申请新的数组。

2 - 使用i，j两个下标。i用于遍历数组，++j用于指向下一个不重复的数的位置。

class Solution {
public:
int removeDuplicates(vector<int>& nums) {
if(nums.size()==0) return 0;
int j=0;
//使用下标i对数组进行遍历
for(int i=1;i<nums.size();i++){
//发现不重复的数，则将其赋值到++j指示的位置
if(nums[j]!=nums[i]){
nums[++j] = nums[i];
}
}
return j+1;
}
};