给定一个数字,任务是设置一个数字的所有偶数位。位的位置从LSB(最低有效位)到MSB(最高有效位)进行计数。 LSB的位置被认为是1。
例子 :
Input : 20
Output : 30
Binary representation of 20 is
10100. After setting
even bits, we get 11110
Input : 10
Output : 10
方法1:
1.首先生成一个包含偶数位置位的数字。
2.在原始号码上加上OR。注意1 | 1 = 1和1 | 0 = 1。
让我们用下面的代码了解这种方法。
C++
// Simple CPP program to set all even
// bits of a number
#include
using namespace std;
// Sets even bits of n and returns
// modified number.
int evenbitsetnumber(int n)
{
// Generate 101010...10 number and
// store in res.
int count = 0, res = 0;
for (int temp = n; temp > 0; temp >>= 1) {
// if bit is even then generate
// number and or with res
if (count % 2 == 1)
res |= (1 << count);
count++;
}
// return OR number
return (n | res);
}
int main()
{
int n = 10;
cout << evenbitsetnumber(n);
return 0;
}
Java
// Simple Java program to set all even
// bits of a number
class GFG
{
// Sets even bits of n and returns
// modified number.
static int evenbitsetnumber(int n)
{
// Generate 101010...10 number and
// store in res.
int count = 0, res = 0;
for (int temp = n; temp > 0; temp >>= 1) {
// if bit is even then generate
// number and or with res
if (count % 2 == 1)
res |= (1 << count);
count++;
}
// return OR number
return (n | res);
}
// Driver code
public static void main(String[] args)
{
int n = 4;
System.out.println(evenbitsetnumber(n));
}
}
// This code is contributed
// by prerna saini.
Python3
# Simple Python program to set all even
# bits of a number
# Sets even bits of n and returns
# modified number.
def evenbitsetnumber(n):
# Generate 101010...10 number and
# store in res.
count = 0
res = 0
temp = n
while(temp > 0):
# if bit is even then generate
# number and or with res
if (count % 2 == 1):
res |= (1 << count)
count+=1
temp >>= 1
# return OR number
return (n | res)
n = 10
print(evenbitsetnumber(n))
# This code is contributed
# by Smitha Dinesh Semwal
C#
// Simple C# program to set
// all even bits of a number
using System;
class GFG
{
// Sets even bits of n and
// returns modified number.
static int evenbitsetnumber(int n) {
// Generate 101010...10 number
// and store in res.
int count = 0, res = 0;
for (int temp = n; temp > 0; temp >>= 1) {
// if bit is even then generate
// number and or with res
if (count % 2 == 1)
res |= (1 << count);
count++;
}
// return OR number
return (n | res);
}
// Driver code
public static void Main()
{
int n = 4;
Console.WriteLine(evenbitsetnumber(n));
}
}
// This code is contributed by vt_m.
PHP
0; $temp >>= 1)
{
// if bit is even then generate
// number and or with res
if ($count % 2 == 1)
$res |= (1 << $count);
$count++;
}
// return OR number
return ($n | $res);
}
//Driver Code
$n = 10;
echo evenbitsetnumber($n);
//This Code is contributed by mits
?>
Javascript
C++
// Efficient CPP program to set all even
// bits of a number
#include
using namespace std;
// return msb set number
int getmsb(int n)
{
// set all bits
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// return msb
// increment n by 1
// and shift by 1
return (n + 1) >> 1;
}
// return even seted number
int getevenbits(int n)
{
// get msb here
n = getmsb(n);
// generate even bits like 101010..
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// if bits is odd then shift by 1
if (n & 1)
n = n >> 1;
// return even set bits number
return n;
}
// set all even bits here
int setallevenbits(int n)
{
// take or with even set bits number
return n | getevenbits(n);
}
int main()
{
int n = 10;
cout << setallevenbits(n);
return 0;
}
Java
// Efficient Java program to
// set all even bits of a number
import java.io.*;
class GFG
{
// return msb set number
static int getmsb(int n)
{
// set all bits
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// return msb
// increment n by 1
// and shift by 1
return (n + 1) >> 1;
}
// return even seted number
static int getevenbits(int n)
{
// get msb here
n = getmsb(n);
// generate even
// bits like 101010..
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// if bits is odd
// then shift by 1
if ((n & 1) == 1)
n = n >> 1;
// return even
// set bits number
return n;
}
// set all even bits here
static int setallevenbits(int n)
{
// take or with even
// set bits number
return n | getevenbits(n);
}
// Driver Code
public static void main (String[] args)
{
int n = 10;
System.out.println(setallevenbits(n));
}
}
// This code is contributed by ajit
Python3
# Efficient Python 3
# program to set all even
# bits of a number
# return msb set number
def getmsb(n):
# set all bits
n |= n >> 1
n |= n >> 2
n |= n >> 4
n |= n >> 8
n |= n >> 16
# return msb
# increment n by 1
# and shift by 1
return (n + 1) >> 1
# return even seted number
def getevenbits(n):
# get msb here
n = getmsb(n)
# generate even bits like 101010..
n |= n >> 2
n |= n >> 4
n |= n >> 8
n |= n >> 16
# if bits is odd then shift by 1
if (n & 1):
n = n >> 1
# return even set bits number
return n
# set all even bits here
def setallevenbits(n):
# take or with even set bits number
return n | getevenbits(n)
n = 10
print(setallevenbits(n))
# This code is contributed by
# Smitha Dinesh Semwal
C#
// Efficient C# program to
// set all even bits of a number
using System;
class GFG
{
// return msb set number
static int getmsb(int n)
{
// set all bits
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// return msb
// increment n by 1
// and shift by 1
return (n + 1) >> 1;
}
// return even seted number
static int getevenbits(int n)
{
// get msb here
n = getmsb(n);
// generate even
// bits like 101010..
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// if bits is odd
// then shift by 1
if ((n & 1) == 1)
n = n >> 1;
// return even
// set bits number
return n;
}
// set all even bits here
static int setallevenbits(int n)
{
// take or with even
// set bits number
return n | getevenbits(n);
}
// Driver Code
public static void Main ()
{
int n = 10;
Console.WriteLine(setallevenbits(n));
}
}
// This code is contributed by aj_36
PHP
> 1;
$n |= $n >> 2;
$n |= $n >> 4;
$n |= $n >> 8;
$n |= $n >> 16;
// return msb
// increment n by 1
// and shift by 1
return ($n + 1) >> 1;
}
// return even seted number
function getevenbits($n)
{
// get msb here
$n = getmsb($n);
// generate even bits
// like 101010..
$n |= $n >> 2;
$n |= $n >> 4;
$n |= $n >> 8;
$n |= $n >> 16;
// if bits is odd then
// shift by 1
if ($n & 1)
$n = $n >> 1;
// return even set
// bits number
return $n;
}
// set all even bits here
function setallevenbits($n)
{
// take or with even
// set bits number
return $n | getevenbits($n);
}
//Driver code
$n = 10;
echo setallevenbits($n);
//This code is contributed by mits
?>
输出:
10
方法2(32位数字的AO(1)解决方案)
C++
// Efficient CPP program to set all even
// bits of a number
#include
using namespace std;
// return msb set number
int getmsb(int n)
{
// set all bits
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// return msb
// increment n by 1
// and shift by 1
return (n + 1) >> 1;
}
// return even seted number
int getevenbits(int n)
{
// get msb here
n = getmsb(n);
// generate even bits like 101010..
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// if bits is odd then shift by 1
if (n & 1)
n = n >> 1;
// return even set bits number
return n;
}
// set all even bits here
int setallevenbits(int n)
{
// take or with even set bits number
return n | getevenbits(n);
}
int main()
{
int n = 10;
cout << setallevenbits(n);
return 0;
}
Java
// Efficient Java program to
// set all even bits of a number
import java.io.*;
class GFG
{
// return msb set number
static int getmsb(int n)
{
// set all bits
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// return msb
// increment n by 1
// and shift by 1
return (n + 1) >> 1;
}
// return even seted number
static int getevenbits(int n)
{
// get msb here
n = getmsb(n);
// generate even
// bits like 101010..
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// if bits is odd
// then shift by 1
if ((n & 1) == 1)
n = n >> 1;
// return even
// set bits number
return n;
}
// set all even bits here
static int setallevenbits(int n)
{
// take or with even
// set bits number
return n | getevenbits(n);
}
// Driver Code
public static void main (String[] args)
{
int n = 10;
System.out.println(setallevenbits(n));
}
}
// This code is contributed by ajit
Python3
# Efficient Python 3
# program to set all even
# bits of a number
# return msb set number
def getmsb(n):
# set all bits
n |= n >> 1
n |= n >> 2
n |= n >> 4
n |= n >> 8
n |= n >> 16
# return msb
# increment n by 1
# and shift by 1
return (n + 1) >> 1
# return even seted number
def getevenbits(n):
# get msb here
n = getmsb(n)
# generate even bits like 101010..
n |= n >> 2
n |= n >> 4
n |= n >> 8
n |= n >> 16
# if bits is odd then shift by 1
if (n & 1):
n = n >> 1
# return even set bits number
return n
# set all even bits here
def setallevenbits(n):
# take or with even set bits number
return n | getevenbits(n)
n = 10
print(setallevenbits(n))
# This code is contributed by
# Smitha Dinesh Semwal
C#
// Efficient C# program to
// set all even bits of a number
using System;
class GFG
{
// return msb set number
static int getmsb(int n)
{
// set all bits
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// return msb
// increment n by 1
// and shift by 1
return (n + 1) >> 1;
}
// return even seted number
static int getevenbits(int n)
{
// get msb here
n = getmsb(n);
// generate even
// bits like 101010..
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
// if bits is odd
// then shift by 1
if ((n & 1) == 1)
n = n >> 1;
// return even
// set bits number
return n;
}
// set all even bits here
static int setallevenbits(int n)
{
// take or with even
// set bits number
return n | getevenbits(n);
}
// Driver Code
public static void Main ()
{
int n = 10;
Console.WriteLine(setallevenbits(n));
}
}
// This code is contributed by aj_36
的PHP
> 1;
$n |= $n >> 2;
$n |= $n >> 4;
$n |= $n >> 8;
$n |= $n >> 16;
// return msb
// increment n by 1
// and shift by 1
return ($n + 1) >> 1;
}
// return even seted number
function getevenbits($n)
{
// get msb here
$n = getmsb($n);
// generate even bits
// like 101010..
$n |= $n >> 2;
$n |= $n >> 4;
$n |= $n >> 8;
$n |= $n >> 16;
// if bits is odd then
// shift by 1
if ($n & 1)
$n = $n >> 1;
// return even set
// bits number
return $n;
}
// set all even bits here
function setallevenbits($n)
{
// take or with even
// set bits number
return $n | getevenbits($n);
}
//Driver code
$n = 10;
echo setallevenbits($n);
//This code is contributed by mits
?>
输出:
10