Count triplets with sum smaller than X.cpp

class Solution{
	
	
	public:
	long long countTriplets(long long arr[], int n, long long sum)
	{
	    // Your code goes here
	    sort(arr,arr+n);
	    
	        int ans=0;
	    
	    for(int i=0;i<n-2;i++){
	        
	        int j=i+1;
	        int k=n-1;
	   
	       
	        while(k>j){
	            if(arr[i]+arr[j]+arr[k]>=sum){
	                k--;
	            }
	            else{
	                ans+=(k-j);
	                j++;
	            }
	        }
	    }
	    return ans;
	}
		 

};