完整二叉树的最小数量，以使叶子的数量为N

给定一个整数N和无限个不同深度的完整二叉树，任务是选择最小数量的树，以使每棵树中的叶节点总数为N。

例子：

Input: N = 7
Output: 3
Trees with depths 2, 1 and 0 can be picked
with the number of leaf nodes as 4, 2 and 1 respectively.
(4 + 2 + 1) = 7

Input: N = 1
Output: 1

方法：由于完整的二叉树中叶节点的数量始终是2的幂。因此，现在问题被简化为寻找2的幂，当将它们相加时会得到N，以使总和中的项总数最小，这是所需的答案。
由于2的每个幂在其二进制表示中仅包含一个’1’，因此N将包含与总和中的项数相同数量的’1’(假设我们采用最少的项数)。因此，问题进一步减少为找到N中的设置位数，使用本文中使用的方法可以很容易地计算出该位数。

下面是上述方法的实现：

C++

// C++ implementation of the approach
#include 
using namespace std;
  
// Function to return the minimum
// count of trees required
int minTrees(int n)
{
  
    // To store the count of
    // set bits in n
    int count = 0;
  
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}
  
// Driver code
int main()
{
    int n = 7;
  
    cout << minTrees(n);
  
    return 0;
}

Java

// Java implementation of the approach
class GFG
{
  
// Function to return the minimum
// count of trees required
static int minTrees(int n)
{
  
    // To store the count of
    // set bits in n
    int count = 0;
  
    while (n > 0)
    {
        n &= (n - 1);
        count++;
    }
    return count;
}
  
// Driver code
public static void main(String[] args)
{
    int n = 7;
  
    System.out.print(minTrees(n));
}
}
  
// This code is contributed by 29AjayKumar

Python3

# Python3 implementation of the approach
  
# Function to return the minimum
# count of trees required
def minTrees(n):
  
    # To store the count of
    # set bits in n
    count = 0;
  
    while (n):
        n &= (n - 1);
        count += 1;
    return count;
  
# Driver code
if __name__ == '__main__':
    n = 7;
    print(minTrees(n));
  
# This code is contributed by 29AjayKumar

C#

// C# implementation of the approach
using System;
  
class GFG
{
  
    // Function to return the minimum
    // count of trees required
    static int minTrees(int n)
    {
      
        // To store the count of
        // set bits in n
        int count = 0;
      
        while (n > 0)
        {
            n &= (n - 1);
            count++;
        }
        return count;
    }
      
    // Driver code
    public static void Main()
    {
        int n = 7;
      
        Console.Write(minTrees(n));
    }
}
  
// This code is contributed by AnkitRai01

输出：

3