Function return the total palindromic subsequence
int countPS ( int i , int j ) { if ( i > j ) return 0 ; if ( dp [ i ] [ j ] != -1 ) return dp [ i ] [ j ] ; if ( i == j ) return dp [ i ] [ j ] = 1 ; else if ( str [ i ] == str [ j ] ) return dp [ i ] [ j ] = countPS ( i + 1 , j ) + countPS ( i , j - 1 ) + 1 ; else return dp [ i ] [ j ] = countPS ( i + 1 , j ) + countPS ( i , j - 1 ) - countPS ( i + 1 , j - 1 ) ; }