【C++】【LeetCode】26. Remove Duplicates from Sorted Array

题目

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

因为不能使用多余内存，所以用indexOfInsert来记录下一个可以插入的位置，然后从头遍历数组，跳过所有重复的数，将其中一个插入indexOfInsert位置。

代码

class Solution {
public:
int removeDuplicates(vector<int>& nums) {
int indexOfInsert = 0;
for (int i=0; i<nums.size(); i++) {
while (i+1<nums.size() && nums[i]==nums[i+1]) i++;
nums[indexOfInsert] = nums[i];
indexOfInsert++;
}
return indexOfInsert;
}
};