Remove Duplicates from Sorted Array II 題解

題目來源：https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/description/

Description

Follow up for "Remove Duplicates":

What if duplicates are allowed at most twice?

Example

Given sorted array nums = [1,1,1,2,2,3],

Your function should return length = 5

Solution

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        if (nums.empty())
            return 0;
        int size = nums.size();
        int
 
 id = 1;
        int dupTimes = 0;
        for (int i = 1; i < size; i++) {
            if (nums[i] != nums[i - 1]) {
                nums[id++] = nums[i];
                dupTimes = 0;
            } else {
                ++dupTimes;
                if (dupTimes < 2)
                    nums[id++] = nums[i];
            }
        }
        return
 
 id;
    }
};

解題描述

這道題題意是第一版的進階：對已經排序的數組進行原地去重（即不使用額外空間），但是允許重復元素最多出現2次。這裏的解法跟第一版基本相同，只是多用了一個計數器dupTimes，每次有重復元素就計數，沒有重復元素就歸零，重復不超過2次就與不重復視為一樣。

[Leetcode] Remove Duplicates from Sorted Array II