计数给定 N 加 1 后改变的位数
给定一个整数
。任务是找出给定数字加 1 后改变的位数。
示例 :
Input : N = 5
Output : 2
After adding 1 to 5 it becomes 6.
Binary representation of 5 is 101.
Binary representation of 6 is 110.
So, no. of bits changed is 2.
Input : N = 1
Output : 2
有三种方法可以在给定值 N 加 1 后得到的结果中找到改变的位数:
- 方法 1: 给定整数加 1，比较 N 的位数和相加后的结果，统计不匹配的位数。
- 方法 2: 如果将 1 加到 N，则改变的总位数由从右数第一个零的位置定义，即 LSB 为零。在这种情况下，1 被加到 1 上，然后它被改变，并将进位 1 传递到它的下一位，但是如果 1 被加到 0 上，则只有 0 变为 1，并且不再传递进位。
- 方法 3: 当给定数加 1 时，要找出改变的位数，进行 n 和 n+1 的异或运算，计算结果异或值中的设定位数。
以下是方法 3 的实施情况:
C++
// CPP program to find the number
// of changed bit
#include <bits/stdc++.h>
using namespace std;
// Function to find number of changed bit
int findChangedBit(int n)
{
// Calculate xor of n and n+1
int XOR = n ^ (n + 1);
// Count set bits in xor value
int result = __builtin_popcount(XOR);
// Return the result
return result;
}
// Driver function
int main()
{
int n = 6;
cout << findChangedBit(n) << endl;
n = 7;
cout << findChangedBit(n);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find the number
// of changed bit
class GFG
{
// Function to find number of changed bit
static int findChangedBit(int n)
{
// Calculate xor of n and n+1
int XOR = n ^ (n + 1);
// Count set bits in xor value
int result = Integer.bitCount(XOR);
// Return the result
return result;
}
// Driver code
public static void main(String[] args)
{
int n = 6;
System.out.println(findChangedBit(n));
n = 7;
System.out.println(findChangedBit(n));
}
}
// This code contributed by Rajput-Ji
Python 3
# Python 3 program to find the number
# of changed bit
# Function to find number of changed bit
def findChangedBit(n):
# Calculate xor of n and n+1
XOR = n ^ (n + 1)
# Count set bits in xor value
result = bin(XOR).count("1")
# Return the result
return result
# Driver Code
if __name__ == '__main__':
n = 6
print(findChangedBit(n))
n = 7
print(findChangedBit(n))
# This code is contributed by
# Surendra_Gangwar
C
// C# program to find the number
// of changed bit
using System;
class GFG
{
// Function to find number of changed bit
static int findChangedBit(int n)
{
// Calculate xor of n and n+1
int XOR = n ^ (n + 1);
// Count set bits in xor value
int result = bitCount(XOR);
// Return the result
return result;
}
static int bitCount(int x)
{
// To store the count
// of set bits
int setBits = 0;
while (x != 0)
{
x = x & (x - 1);
setBits++;
}
return setBits;
}
// Driver code
public static void Main(String[] args)
{
int n = 6;
Console.WriteLine(findChangedBit(n));
n = 7;
Console.WriteLine(findChangedBit(n));
}
}
/* This code contributed by PrinciRaj1992 */
java 描述语言
<script>
// Javascript program to find the number
// of changed bit
// Function to find number of changed bit
function findChangedBit(n)
{
// Calculate xor of n and n+1
let XOR = n ^ (n + 1);
// Count set bits in xor value
let result = bitCount(XOR);
// Return the result
return result;
}
function bitCount(x)
{
// To store the count
// of set bits
let setBits = 0;
while (x != 0)
{
x = x & (x - 1);
setBits++;
}
return setBits;
}
// Driver function
let n = 6;
document.write(findChangedBit(n) + "<br>");
n = 7;
document.write(findChangedBit(n));
</script>
Output:
1
4
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