title: Count Even Length Binary Sequences With Same Sum Of First And Second Half Bits 1
signature: double countEvenLengthBinarySequencesWithSameSumOfFirstAndSecondHalfBits1(int n) {
test_code: #include <algorithm>
  #include <assert.h>
  #include <cstdlib>
  #include <iostream>
  #include <map>
  #include <set>
  #include <string>
  #include <tuple> 
  #include <unordered_map>
  #include <vector>
  #include <math.h>
  #include <cmath>
  #include <bits/stdc++.h>
  #include <numeric>
  #include <functional>
  
  using namespace std;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(double actual, double expected){
      return abs(actual - expected) < 1e-09;
  }
  
  string driver(int n, double expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(n), expected)){
              return "PASSED";
          }
          return "FAILED";
      }
      catch (const std::overflow_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::runtime_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::exception& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (...)
      {
          return "UNK_ERROR";
      }
  }
  
  int main() {
      string result = "";
  
      result = driver(25, 126410606437752.0); 
      cout << "TEST-" << 0 << "..."
           <<  result
           << "\n";
  
      result = driver(18, 9075135300.0); 
      cout << "TEST-" << 1 << "..."
           <<  result
           << "\n";
  
      result = driver(17, 2333606220.0); 
      cout << "TEST-" << 2 << "..."
           <<  result
           << "\n";
  
      result = driver(8, 12870.0); 
      cout << "TEST-" << 3 << "..."
           <<  result
           << "\n";
  
      result = driver(8, 12870.0); 
      cout << "TEST-" << 4 << "..."
           <<  result
           << "\n";
  
      return 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;
  }