Count number of triplets in an array having sum in the range [ a , b ] | Java program to count triplets with sum that lies in given range [ a , b ] . ; Function to count triplets ; Initialize result ; Fix the first element as A [ i ] ; Fix the second element as A [ j ] ; Now look for the third number ; Driver Code
import java . util . * ; class GFG { public static int countTriplets ( int [ ] arr , int n , int a , int b ) { int ans = 0 ; for ( int i = 0 ; i < n - 2 ; i ++ ) { for ( int j = i + 1 ; j < n - 1 ; j ++ ) { for ( int k = j + 1 ; k < n ; k ++ ) { if ( arr [ i ] + arr [ j ] + arr [ k ] >= a && arr [ i ] + arr [ j ] + arr [ k ] <= b ) { ans ++ ; } } } } return ans ; } public static void main ( String [ ] args ) { int [ ] arr = { 2 , 7 , 5 , 3 , 8 , 4 , 1 , 9 } ; int n = arr . length ; int a = 8 , b = 16 ; System . out . println ( " " + countTriplets ( arr , n , a , b ) ) ; } }