Leetcode: 26. Remove Duplicates from Sorted Array

Description

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.

Example

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

• 去重問題沒啥好說的吧
• 一個下標為去重後的索引，一個下標是去重前的索引

代碼

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        int len = nums.size();
        if(len <= 1) return len;
        
        int begin = -1, i = 0;
        while(i < len){
            if(i > 0 && nums[i] == nums[i - 1]){
                ++i;
                continue;
            }
            
            ++begin;
            nums[begin] = nums[i];
            ++i;
        }
        
        return begin + 1;
    }
};