Missing Number

class Solution {
public:
    int missingNumber(vector<int>& nums) {
        int size=nums.size();
        int * myArray=new int[size+1];
        memset(myArray,0,sizeof(int)*(size+1));
        for(int i=0;i<size;i++)
        {
            myArray[nums[i]]=1;
        }
        int index=0;
        for(;index<size+1;index++)
        {
            if(myArray[index]==0)
                break;
        }
        return index;
        
    }
};