Dado un entero positivo N, averigüe cuántos enteros positivos estrictamente menores que N tienen el mismo número de bits establecidos que N.
Ejemplos:
Input : 8 Output :3 Explanation: Binary representation of 8 : 1000, so number of set bits in 8 is 1. So the integers less than 8 with same number of set bits are : 4, 2, 1 Input :1 Output :0 Input :4 Output :2
Acercarse:
1. Using __builtin_popcount() inbuilt function, count set bits in N and store into a temp variable 2. Iterate from n-1 to 1 and also count set bits in i using __builtin_popcount() function 3. Now, compare temp with __builtin_popcount(i) 4. If both are equal then increment counter variable 5. Return counter
A continuación se muestra la implementación del enfoque anterior.
C++
// CPP program to find numbers less than N
// that have same Number Of Set Bits As N
#include <iostream>
using namespace std;
int smallerNumsWithSameSetBits(int n)
{
// __builtin_popcount function that count
// set bits in n
int temp = __builtin_popcount(n);
// Iterate from n-1 to 1
int count = 0;
for (int i = n - 1; i > 0; i--) {
// check if the number of set bits
// equals to temp increment count
if (temp == __builtin_popcount(i))
count++;
}
return count;
}
// Driver Code
int main()
{
int n = 4;
cout << smallerNumsWithSameSetBits(n);
return 0;
}
Java
// Java program to find numbers less than N
// that have same Number Of Set Bits As N
class GFG {
// returns number of set bits in a number
static int __builtin_popcount(int n)
{
int d, t = 0;
while(n > 0)
{
d = n % 2;
n = n / 2;
if(d == 1)
t++;
}
return t;
}
static int smallerNumsWithSameSetBits(int n)
{
// __builtin_popcount function that count
// set bits in n
int temp = __builtin_popcount(n);
// Iterate from n-1 to 1
int count = 0;
for (int i = n - 1; i > 0; i--) {
// check if the number of set bits
// equals to temp increment count
if (temp == __builtin_popcount(i))
count++;
}
return count;
}
// Driver Code
public static void main(String[] args)
{
int n = 4;
System.out.println(
smallerNumsWithSameSetBits(n));
}
}
// This code is contributed by Arnab Kundu.
Python3
# Python3 program to find numbers # less than N that have same # Number Of Set Bits As N def __builtin_popcount(n) : t = 0 while(n > 0) : d = n % 2 n = int(n / 2) if(d == 1) : t = t + 1 return t def smallerNumsWithSameSetBits(n) : # __builtin_popcount function # that count set bits in n temp = __builtin_popcount(n) # Iterate from n-1 to 1 count = 0 for i in range(n-1,0,-1) : # check if the number of # set bits equals to temp # increment count if (temp == __builtin_popcount(i)) : count = count + 1 return count # Driver Code n = 4 print (smallerNumsWithSameSetBits(n)) # This code is contributed by # Manish Shaw(manishshaw1)
C#
// C# program to find numbers less than N
// that have same Number Of Set Bits As N
using System;
class GFG {
// returns number of set bits in a number
static int __builtin_popcount(int n)
{
int d, t = 0;
while(n > 0)
{
d = n % 2;
n = n / 2;
if(d == 1)
t++;
}
return t;
}
static int smallerNumsWithSameSetBits(int n)
{
// __builtin_popcount function that count
// set bits in n
int temp = __builtin_popcount(n);
// Iterate from n-1 to 1
int count = 0;
for (int i = n - 1; i > 0; i--) {
// check if the number of set bits
// equals to temp increment count
if (temp == __builtin_popcount(i))
count++;
}
return count;
}
// Driver Code
static public void Main(String []args)
{
int n = 4;
Console.WriteLine(
smallerNumsWithSameSetBits(n));
}
}
// This code is contributed by Arnab Kundu.
PHP
<?php
// PHP program to find numbers
// less than N that have same
// Number Of Set Bits As N
function __builtin_popcount($n)
{
$t = 0;
while($n > 0)
{
$d = $n % 2;
$n = intval($n / 2);
if($d == 1)
$t++;
}
return $t;
}
function smallerNumsWithSameSetBits($n)
{
// __builtin_popcount function
// that count set bits in n
$temp = __builtin_popcount($n);
// Iterate from n-1 to 1
$count = 0;
for ($i = $n - 1; $i > 0; $i--)
{
// check if the number of
// set bits equals to temp
// increment count
if ($temp == __builtin_popcount($i))
$count++;
}
return $count;
}
// Driver Code
$n = 4;
echo (smallerNumsWithSameSetBits($n));
// This code is contributed by
// Manish Shaw(manishshaw1)
?>
Javascript
<script>
// Javascript program to find numbers less than N
// that have same Number Of Set Bits As N
// returns number of set bits in a number
function __builtin_popcount(n)
{
var d, t = 0;
while(n > 0)
{
d = n % 2;
n = parseInt(n / 2);
if(d == 1)
t++;
}
return t;
}
function smallerNumsWithSameSetBits(n)
{
// __builtin_popcount function that count
// set bits in n
var temp = __builtin_popcount(n);
// Iterate from n-1 to 1
var count = 0;
for (var i = n - 1; i > 0; i--) {
// check if the number of set bits
// equals to temp increment count
if (temp == __builtin_popcount(i))
count++;
}
return count;
}
// Driver Code
var n = 4;
document.write( smallerNumsWithSameSetBits(n));
</script>
Producción:
2