给定数组arr [] ,任务是计算数组中所有有效对。如果func(arr [i])+ func(arr [j])= func(XOR(arr [i],arr [j])),则说成对(arr [i],arr [j])是有效的其中FUNC(x)返回比特集合x中的数目。
例子:
Input: arr[] = {2, 3, 4, 5, 6}
Output: 3
(2, 4), (2, 5) and (3, 4) are the only valid pairs.
Input: arr[] = {12, 13, 34, 25, 6}
Output: 4
方法:迭代每个可能的对,并检查该对是否满足给定条件。如果满足条件,则更新计数=计数+ 1 。最后打印计数。
下面是上述方法的实现:
C++
// C++ implementation of the approach
#include
using namespace std;
// Function to return the number
// of set bits in n
int setBits(int n)
{
int count = 0;
while (n) {
n = n & (n - 1);
count++;
}
return count;
}
// Function to return the count of required pairs
int countPairs(int a[], int n)
{
int count = 0;
for (int i = 0; i < n - 1; i++) {
// Set bits for first element of the pair
int setbits_x = setBits(a[i]);
for (int j = i + 1; j < n; j++) {
// Set bits for second element of the pair
int setbits_y = setBits(a[j]);
// Set bits of the resultant number which is
// the XOR of both the elements of the pair
int setbits_xor_xy = setBits(a[i] ^ a[j]);
// If the condition is satisfied
if (setbits_x + setbits_y == setbits_xor_xy)
// Increment the count
count++;
}
}
// Return the total count
return count;
}
// Driver code
int main()
{
int a[] = { 2, 3, 4, 5, 6 };
int n = sizeof(a) / sizeof(a[0]);
cout << countPairs(a, n);
}
Java
// Java implementation of the approach
import java.io.*;
class GFG
{
// Function to return the number
// of set bits in n
static int setBits(int n)
{
int count = 0;
while (n > 0)
{
n = n & (n - 1);
count++;
}
return count;
}
// Function to return the count of
// required pairs
static int countPairs(int a[], int n)
{
int count = 0;
for (int i = 0; i < n - 1; i++)
{
// Set bits for first element
// of the pair
int setbits_x = setBits(a[i]);
for (int j = i + 1; j < n; j++)
{
// Set bits for second element
// of the pair
int setbits_y = setBits(a[j]);
// Set bits of the resultant number which is
// the XOR of both the elements of the pair
int setbits_xor_xy = setBits(a[i] ^ a[j]);
// If the condition is satisfied
if (setbits_x + setbits_y == setbits_xor_xy)
// Increment the count
count++;
}
}
// Return the total count
return count;
}
// Driver code
public static void main (String[] args)
{
int []a = { 2, 3, 4, 5, 6 };
int n = a.length;
System.out.println(countPairs(a, n));
}
}
// This code is contributed by ajit.
Python3
# Python 3 implementation of the approach
# Function to return the number
# of set bits in n
def setBits(n):
count = 0
while (n):
n = n & (n - 1)
count += 1
return count
# Function to return the count
# of required pairs
def countPairs(a, n):
count = 0
for i in range(0, n - 1, 1):
# Set bits for first element
# of the pair
setbits_x = setBits(a[i])
for j in range(i + 1, n, 1):
# Set bits for second element
# of the pair
setbits_y = setBits(a[j])
# Set bits of the resultant number
# which is the XOR of both the
# elements of the pair
setbits_xor_xy = setBits(a[i] ^ a[j]);
# If the condition is satisfied
if (setbits_x +
setbits_y == setbits_xor_xy):
# Increment the count
count += 1
# Return the total count
return count
# Driver code
if __name__ == '__main__':
a = [2, 3, 4, 5, 6]
n = len(a)
print(countPairs(a, n))
# This code is contributed by
# Sanjit_Prasad
C#
// C# implementation of the approach
using System;
class GFG
{
// Function to return the number
// of set bits in n
static int setBits(int n)
{
int count = 0;
while (n > 0)
{
n = n & (n - 1);
count++;
}
return count;
}
// Function to return the count of
// required pairs
static int countPairs(int []a, int n)
{
int count = 0;
for (int i = 0; i < n - 1; i++)
{
// Set bits for first element
// of the pair
int setbits_x = setBits(a[i]);
for (int j = i + 1; j < n; j++)
{
// Set bits for second element
// of the pair
int setbits_y = setBits(a[j]);
// Set bits of the resultant number which is
// the XOR of both the elements of the pair
int setbits_xor_xy = setBits(a[i] ^ a[j]);
// If the condition is satisfied
if (setbits_x + setbits_y == setbits_xor_xy)
// Increment the count
count++;
}
}
// Return the total count
return count;
}
// Driver code
public static void Main()
{
int []a = { 2, 3, 4, 5, 6 };
int n = a.Length;
Console.Write(countPairs(a, n));
}
}
// This code is contributed
// by Akanksha Rai
PHP
Javascript
输出:
3