Remove Duplicates from Sorted Array

    int removeDuplicates(int A[], int n) {
    // Start typing your C/C++ solution below
    // DO NOT write int main() function
    int i=0;
    int j;
    if (n<=1) return n;

    for (j=1;j<n;j++)
    {            
        if (A[j] != A[i])
        {                
            A[++i]=A[j];
        }
    }
    return i+1;
}

class Solution {
public:
int removeDuplicates(int arr[], int n) {
    // Start typing your C/C++ solution below
    // DO NOT write int main() function
if(n<=1)
    return n;
int insertPos = 0; 
for (int i = 1; i < n; i++)
{
    if (arr[i] != arr[insertPos])
        arr[++insertPos] = arr[i];
}
return insertPos+1;
}
};

if( n <= 1)
  return n;
int begin = 0;
int end = 1;
while( end < n )
{
    if( A[begin] == A[end])
        end++;
    else 
        {
            A[++begin] = A[end++];
        }
}
return begin+1;

public int removeDuplicates(int[] A) {

    if(A == null || A.length == 0)
        return 0;

    int element = A[0];
    int index = 0;

    for(int i = 0; i < A.length; i++) {
        if(element != A[i]) {
            index++;
            A[index] = A[i];
            element = A[i];
        }
    }

    return index + 1;
}

int removeDuplicates(int A[], int n) {
    // Start typing your C/C++ solution below
    // DO NOT write int main() function
        int result;
        int next =0; 
        if (n==0) return 0; 
        int temp = A[0];
        result =1;
        next++;
        for(int i =1; i < n;i++){
            if(A[i] != temp){
                A[next] = A[i];
                temp = A[i];
                next++;
                result++;
            }
        }
        return result;
}

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        int j = 0;
        for (int i = 1; i < n; ++i) {
            if (A[i] != A[j]) {
                A[++j] = A[i];
            }
        }
        // n doesn't like to be checked at the very top :(
        return (++j) * (!!n);
    }
};

int removeDuplicates(int A[], int n) {
    //ptr point to the last element of non-duplicate array
    if(n==0) return 0;
    if(n==1) return 1;
    int ptr = 0;
    int i;
    for(i=1;i<n;i++){
        if(A[i]==A[ptr]){
        }else{
            A[++ptr] = A[i];
        }
    }
    return ptr+1;
}

int removeDuplicates(int A[], int n) {
    int cur = 0;
    if(n==0) {
        return n;
    }
    for(int i=1; i<n; i++) {
        if(A[i] != A[cur]) {
            A[++cur] = A[i];
        }
    }
    return cur+1;
}

Use two pointers, one head, one next. If A[head] == A[next], then move next forward. Otherwise, copy A[next] to A[head+1], then increment both head and next.

int removeDuplicates(int A[], int n) {
    // Start typing your C/C++ solution below
    // DO NOT write int main() function
    if (n == 0 || n == 1) {
        return n;
    }

    int hd = 0, nx = 0;

    for (; nx != n;) {
        if (A[hd] == A[nx]) {
            nx++;
        } else {
            A[++hd] = A[nx++];
        }
    }

    return hd+1;
}

int removeDuplicates(int A[], int n) {
    if (n == 0) return 0;
    int j = 0;
    for (int i = 1; i < n; ++i)
        if (A[i] != A[j])
            A[++j] = A[i];
    return j + 1;
}