LeetCode Remove Duplicates from Sorted Array，leetcodeduplicates

LeetCode Remove Duplicates from Sorted Array，leetcodeduplicates

Remove Duplicates from Sorted Array Total Accepted: 52196 Total Submissions: 165553 My Submissions Question Solution
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 A = [1,1,2],

Your function should return length = 2, and A is now [1,2].

題意：刪除有序數組的重複元素

代碼一：

class Solution {public:    int removeDuplicates(int A[], int n) {        if(n==0)return 0;        int index=0;        for(int i=1;i<n;++i)        {            if(A[i]!=A[i-1])                A[++index]=A[i];        }        return index+1;    }};

161 / 161 test cases passed.
Status: Accepted
Runtime: 37 ms

代碼二（網路擷取）：

// LeetCode, Remove Duplicates from Sorted Array// 使用STL，時間複雜度O(n)，空間複雜度O(1)class Solution {public:int removeDuplicates(int A[], int n) {    return distance(A, unique(A, A + n));    }}

161 / 161 test cases passed.
Status: Accepted
Runtime: 34 ms
在STL中unique函數是一個去重函數， unique的功能是去除相鄰的重複元素(只保留一個),其實它並不真正把重複的元素刪除，是把重複的元素移到後面去了，然後依然儲存到了原數組中，然後 返回去重後最後一個元素的地址，因為unique去除的是相鄰的重複元素，所以一般用之前都會要排一下序。
distance返回兩個迭代器之間的距離。