Numbers - Range Count

                  Numbers - Range Count 

Given N distinct integers, the program must print the number of ranges R present. A range is defined as two or more consecutive integers.

Input Format:
The first line contains N.
The second line contains N integer values separated by a space.

Output Format:
The first line contains R.

Boundary Conditions:
2 <= N <= 100000
1 <= R <= 10000

Example Input/Output 1:
Input:
5
2 1 4 9 3

Output:
1

Explanation:
The only range which is present is 1 2 3 4.
9 is not a range (as a range needs two or more consecutive integers).

Example Input/Output 2:
Input:
7
1 3 11 -15 -20 9 5

Output:

Code:

#include<algorithm>
#include<iostream>
int main(){
    int i,j,flag=0,n,c=0;
    std::cin>>n;
    int arr[n];
    for(i=0;i<n;i++)
        std::cin>>arr[i];
    std::sort(arr,arr+n);
    for(i=0;i<n;i++)
    {
        if(arr[i]+1==arr[i+1])
            flag=1;
        else
        {
            if(flag==1)
            {
                c++;
                flag=0;
            }
        }
    }
 std::cout<<c;
}