给定数字N。任务是使用递归查找二进制表示形式的设置位数。
例子:
Input : 21
Output : 3
21 represesnted as 10101 in binray representation
Input : 16
Output : 1
16 represesnted as 10000 in binray representation
方法:
- 首先,检查号码的最低位。
- 如果LSB为1,则我们将答案加1,然后将数字除以2。
- 如果LSB为0,则将答案加0,然后将其除以2。
- 然后,我们递归地执行步骤(1),直到该数字大于0。
下面是上述方法的实现:
C++
// CPP program to find number
// of set bist in a number
#include
using namespace std;
// Recursive function to find
// number of set bist in a number
int CountSetBits(int n)
{
// Base condition
if (n == 0)
return 0;
// If Least signifiant bit is set
if((n & 1) == 1)
return 1 + CountSetBits(n >> 1);
// If Least significant bit is not set
else
return CountSetBits(n >> 1);
}
// Driver code
int main()
{
int n = 21;
// Function call
cout << CountSetBits(n) << endl;
return 0;
}
Java
// Java program to find number
// of set bist in a number
class GFG
{
// Recursive function to find
// number of set bist in a number
static int CountSetBits(int n)
{
// Base condition
if (n == 0)
return 0;
// If Least signifiant bit is set
if((n & 1) == 1)
return 1 + CountSetBits(n >> 1);
// If Least significant bit is not set
else
return CountSetBits(n >> 1);
}
// Driver code
public static void main (String [] args)
{
int n = 21;
// Function call
System.out.println(CountSetBits(n));
}
}
// This code is contributed by ihritik
Python3
# Python3 program to find number
# of set bist in a number
# Recursive function to find
# number of set bist in a number
def CountSetBits(n):
# Base condition
if (n == 0):
return 0;
# If Least signifiant bit is set
if((n & 1) == 1):
return 1 + CountSetBits(n >> 1);
# If Least signifiant bit is not set
else:
return CountSetBits(n >> 1);
# Driver code
if __name__ == '__main__':
n = 21;
# Function call
print(CountSetBits(n));
# This code is contributed by 29AjayKumar
C#
// C# program to find number
// of set bist in a number
using System;
class GFG
{
// Recursive function to find
// number of set bist in a number
static int CountSetBits(int n)
{
// Base condition
if (n == 0)
return 0;
// If Least signifiant bit is set
if((n & 1) == 1)
return 1 + CountSetBits(n >> 1);
// If Least significant bit is not set
else
return CountSetBits(n >> 1);
}
// Driver code
public static void Main ()
{
int n = 21;
// Function call
Console.WriteLine(CountSetBits(n));
}
}
// This code is contributed by ihritik
输出:
3