检查一个数字是否有交替模式的位|设置-2 O(1)接近
原文:https://www . geesforgeks . org/check-number-bits-alternate-pattern-set-2-O1-approach/
给定正整数 n 。问题是检查这个整数在其二进制表示中是否有替换模式。这里的交替模式是指 n 中的置位和未置位以交替顺序出现。例如- 5 具有交替模式，即 101。 如果有替代图案，则打印“是”，否则打印“否”。 注: 0 < n. 例:
Input : 10
Output : Yes
(10)<sub>10</sub> = (1010)2, has an alternate pattern.
Input : 12
Output : No
(12)<sub>10</sub> = (1100)2, does not have an alternate pattern.
简单方法:在这篇帖子中已经讨论过时间复杂度为 O(n)。 高效方法:以下是步骤:
- 计算 num = n ^ (n > > 1)。如果 n 具有交替模式，那么 n ^ (n > > 1) 操作将产生仅具有设定位的数。 '^' 是按位异或运算。
- 检查号中的所有位是否都设置好了。参考这篇帖子。
C++
// C++ implementation to check if a number
// has bits in alternate pattern
#include <bits/stdc++.h>
using namespace std;
// function to check if all the bits are set or not
// in the binary representation of 'n'
bool allBitsAreSet(unsigned int n)
{
// if true, then all bits are set
if (((n + 1) & n) == 0)
return true;
// else all bits are not set
return false;
}
// function to check if a number
// has bits in alternate pattern
bool bitsAreInAltOrder(unsigned int n)
{
unsigned int num = n ^ (n >> 1);
// to check if all bits are set
// in 'num'
return allBitsAreSet(num);
}
// Driver program to test above
int main()
{
unsigned int n = 10;
if (bitsAreInAltOrder(n))
cout << "Yes";
else
cout << "No";
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java implementation to check if a
// number has bits in alternate pattern
class AlternateSetBits
{
// function to check if all the bits
// are set or not in the binary
// representation of 'n'
static boolean allBitsAreSet(int n)
{
// if true, then all bits are set
if (((n + 1) & n) == 0)
return true;
// else all bits are not set
return false;
}
// function to check if a number
// has bits in alternate pattern
static boolean bitsAreInAltOrder(int n)
{
int num = n ^ (n >>> 1);
// to check if all bits are set
// in 'num'
return allBitsAreSet(num);
}
// Driver Code
public static void main(String args[])
{
int n = 10;
if (bitsAreInAltOrder(n))
System.out.println("Yes");
else
System.out.println("No");
}
}
/* This code is contributed by Danish Kaleem */
Python 3
# Python implementation to check if a number
# has bits in alternate pattern
# function to check if all the bits are set or not
# in the binary representation of 'n'
def allBitsAreSet(n):
# if true, then all bits are set
if (((n + 1) & n) == 0):
return True;
# else all bits are not set
return False;
# function to check if a number
# has bits in alternate pattern
def bitsAreInAltOrder(n):
num = n ^ (n >> 1);
# to check if all bits are set
# in 'num'
return allBitsAreSet(num);
# Driver code
n = 10;
if (bitsAreInAltOrder(n)):
print("Yes");
else:
print("No");
# This code is contributed by PrinciRaj1992
C
// C# implementation to check if a
// number has bits in alternate pattern
using System;
class GFG {
// function to check if all the bits
// are set or not in the binary
// representation of 'n'
static bool allBitsAreSet(int n)
{
// if true, then all bits are set
if (((n + 1) & n) == 0)
return true;
// else all bits are not set
return false;
}
// function to check if a number
// has bits in alternate pattern
static bool bitsAreInAltOrder(int n)
{
int num = n ^ (n >> 1);
// to check if all bits are set
// in 'num'
return allBitsAreSet(num);
}
// Driver Code
public static void Main()
{
int n = 10;
if (bitsAreInAltOrder(n))
Console.WriteLine("Yes");
else
Console.WriteLine("No");
}
}
// This code is contributed by Sam007
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP implementation to check
// if a number has bits in
// alternate pattern
// function to check if all the
// bits are set or not in the
// binary representation of 'n'
function allBitsAreSet($n)
{
// if true, then all
// bits are set
if ((($n + 1) & $n) == 0)
return true;
// else all bits are not set
return false;
}
// function to check if a number
// has bits in alternate pattern
function bitsAreInAltOrder($n)
{
$num = $n ^ ($n >> 1);
// to check if all bits
// are set in 'num'
return allBitsAreSet($num);
}
// Driver Code
$n = 10;
if (bitsAreInAltOrder($n))
echo "Yes";
else
echo "No";
// This code is contributed by aj_36
?>
java 描述语言
<script>
// Javascript implementation to check if a
// number has bits in alternate pattern
// function to check if all the bits
// are set or not in the binary
// representation of 'n'
function allBitsAreSet(n)
{
// if true, then all bits are set
if (((n + 1) & n) == 0)
return true;
// else all bits are not set
return false;
}
// function to check if a number
// has bits in alternate pattern
function bitsAreInAltOrder(n)
{
let num = n ^ (n >>> 1);
// to check if all bits are set
// in 'num'
return allBitsAreSet(num);
}
// driver function
let n = 10;
if (bitsAreInAltOrder(n))
document.write("Yes");
else
document.write("No");
// This code is contributed by code_hunt.
</script>
输出:
Yes
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