Saturday, October 5, 2024
Google search engine
HomeData Modelling & AICentral binomial coefficient

Central binomial coefficient

Given an integer N, the task is to find the N^{th}    Central binomial coefficient
The first few Central binomial coefficients for N = 0, 1, 2, 3… are 
 

1, 2, 6, 20, 70, 252, 924, 3432…..

Examples: 
 

Input: N = 3 
Output: 20 
Explanation: 
N^{th}    Central Binomial Coefficient = \binom{2N}{N}    \binom{2*3}{3}    \frac{6*5*4}{3*2*1}    = 20
Input: N = 2 
Output:
 

 

Approach: The central binomial coefficient is a binomial coefficient of the form \binom{2N}{N}    . The Binomial Coefficient \binom{2N}{N}    can be computed using this approach for a given value N using Dynamic Programming.
For Example: 
 

Central binomial coefficient of N = 3 is given by: 
\binom{2N}{N}    \binom{2*3}{3}    \frac{6*5*4}{3*2*1}    = 20 
 

Below is the implementation of the above approach:
 

C++




// C++ implementation to find the
// Nth Central Binomial Coefficient
 
#include<bits/stdc++.h>
using namespace std;
 
// Function to find the value of
// Nth Central Binomial Coefficient
int binomialCoeff(int n, int k)
{
    int C[n + 1][k + 1];
    int i, j;
 
    // Calculate value of Binomial
    // Coefficient in bottom up manner
    for (i = 0; i <= n; i++)
    {
        for (j = 0; j <= min(i, k); j++)
        {
            // Base Cases
            if (j == 0 || j == i)
                C[i][j] = 1;
 
            // Calculate value
            // using previously
            // stored values
            else
                C[i][j] = C[i - 1][j - 1] +
                        C[i - 1][j];
        }
    }
 
    return C[n][k];
}
 
// Driver Code
int main()
{
    int n = 3;
    int k = n;
    n = 2*n;
    cout << binomialCoeff(n, k);
}


Java




// Java implementation to find the
// Nth Central Binomial Coefficient
class GFG{
     
// Function to find the value of
// Nth Central Binomial Coefficient
static int binomialCoeff(int n, int k)
{
    int[][] C = new int[n + 1][k + 1];
    int i, j;
 
    // Calculate value of Binomial
    // Coefficient in bottom up manner
    for(i = 0; i <= n; i++)
    {
       for(j = 0; j <= Math.min(i, k); j++)
       {
            
          // Base Cases
          if (j == 0 || j == i)
              C[i][j] = 1;
           
          // Calculate value
          // using previously
          // stored values
          else
              C[i][j] = C[i - 1][j - 1] +
                        C[i - 1][j];
       }
    }
    return C[n][k];
}
 
// Driver Code
public static void main(String[] args)
{
    int n = 3;
    int k = n;
    n = 2 * n;
     
    System.out.println(binomialCoeff(n, k));
}
}
 
// This code is contributed by Ritik Bansal


Python3




# C# implementation to find the
# Nth Central Binomial Coefficient
 
# Function to find the value of
# Nth Central Binomial Coefficient
def binomialCoeff(n, k):
     
    C = [[0 for j in range(k + 1)]
            for i in range(n + 1)]
     
    i = 0
    j = 0
     
    # Calculate value of Binomial
    # Coefficient in bottom up manner
    for i in range(n + 1):
        for j in range(min(i, k) + 1):
             
            # Base Cases
            if j == 0 or j == i:
                C[i][j] = 1
                 
            # Calculate value
            # using previously
            # stored values
            else:
                C[i][j] = (C[i - 1][j - 1] +
                           C[i - 1][j])
     
    return C[n][k]
     
# Driver code
if __name__=='__main__':
     
    n = 3
    k = n
    n = 2 * n
     
    print(binomialCoeff(n, k))
         
# This code is contributed by rutvik_56


C#




// C# implementation to find the
// Nth Central Binomial Coefficient
using System;
class GFG{
     
// Function to find the value of
// Nth Central Binomial Coefficient
static int binomialCoeff(int n, int k)
{
    int [,]C = new int[n + 1, k + 1];
    int i, j;
 
    // Calculate value of Binomial
    // Coefficient in bottom up manner
    for(i = 0; i <= n; i++)
    {
       for(j = 0; j <= Math.Min(i, k); j++)
       {
            
          // Base Cases
          if (j == 0 || j == i)
              C[i, j] = 1;
               
          // Calculate value
          // using previously
          // stored values
          else
              C[i, j] = C[i - 1, j - 1] +
                        C[i - 1, j];
       }
    }
    return C[n, k];
}
 
// Driver Code
public static void Main()
{
    int n = 3;
    int k = n;
    n = 2 * n;
     
    Console.Write(binomialCoeff(n, k));
}
}
 
// This code is contributed by Code_Mech


Javascript




<script>
 
// Javascript implementation to find the
// Nth Central Binomial Coefficient
 
// Function to find the value of
// Nth Central Binomial Coefficient
function binomialCoeff(n, k)
{
    var C = Array.from(Array(n+1),()=> Array(k+1));
    var i, j;
 
    // Calculate value of Binomial
    // Coefficient in bottom up manner
    for (i = 0; i <= n; i++)
    {
        for (j = 0; j <= Math.min(i, k); j++)
        {
            // Base Cases
            if (j == 0 || j == i)
                C[i][j] = 1;
 
            // Calculate value
            // using previously
            // stored values
            else
                C[i][j] = C[i - 1][j - 1] +
                        C[i - 1][j];
        }
    }
 
    return C[n][k];
}
 
// Driver Code
var n = 3;
var k = n;
n = 2*n;
document.write( binomialCoeff(n, k));
 
 
</script>


Output: 

20

 

Time Complexity: O(N * K)
Auxiliary Space: O(N * K)

Feeling lost in the world of random DSA topics, wasting time without progress? It’s time for a change! Join our DSA course, where we’ll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 neveropen!

RELATED ARTICLES

Most Popular

Recent Comments