title: Count Even Length Binary Sequences With Same Sum Of First And Second Half Bits 1
signature: pub fn count_even_length_binary_sequences_with_same_sum_of_first_and_second_half_bits_1(n: i32) -> f64 {
test_code: use std::collections::HashMap;
  use std::collections::HashSet;
  use std::cmp::*;
  use std::collections::*;
  use std::fmt::*; 
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  pub fn validate_solution(actual: f64, expected: f64)->bool{
  return (actual - expected).abs() < 1e-09
  }
  pub fn driver(n: i32, expected: f64)->String{
      if validate_solution(PLACEHOLDER_FN_NAME(n), expected) {
        return "PASSED".to_string();
      };
      return "FAILED".to_string();
  
  }
  
  fn main() {
      println!("TEST-0...{}", driver(
        25, 
        126410606437752.0
      ));
      
      println!("TEST-1...{}", driver(
        18, 
        9075135300.0
      ));
      
      println!("TEST-2...{}", driver(
        17, 
        2333606220.0
      ));
      
      println!("TEST-3...{}", driver(
        8, 
        12870.0
      ));
      
      println!("TEST-4...{}", driver(
        8, 
        12870.0
      ));
      
  }
source_py: def count_even_length_binary_sequences_with_same_sum_of_first_and_second_half_bits_1(n):
      nCr = 1
      res = 1
      for r in range(1, (n + 1)):
          nCr = ((nCr * ((n + 1) - r)) / r)
          res += (nCr * nCr)
      return res
source_cpp: int count_even_length_binary_sequences_with_same_sum_of_first_and_second_half_bits_1(int n) {
    int nCr = 1, res = 1;
    for ( int r = 1;
    r <= n;
    r ++ ) {
      nCr = ( nCr * ( n + 1 - r ) ) / r;
      res += nCr * nCr;
    }
    return res;
  }