给定N个元素的数组arr和另一个包含K值的数组Q ,任务是在数组arr中与数组Q中的每个元素K进行异或运算后,打印出奇数和偶数置位的数组arr中的元素计数。
例子:
Input: arr[] = { 2, 7, 4, 5, 3 }, Q[] = { 3, 4, 12, 6 }
Output: 2 3
3 2
2 3
2 3
Input: arr[] = { 7, 1, 6, 5, 11 }, Q[] = { 2, 10, 3, 6 }
Output: 3 2
2 3
2 3
2 3
方法:
- 两个均具有奇数或偶数置位的元素的异或结果将导致偶数置位。
- 两个元素的异或结果为奇数位,一个为奇数,另一个为偶数,反之亦然。
- 使用Brian Kernighan的算法预先计算所有数组元素的偶数和奇数位的元素计数。
- 对于Q的所有元素,计数置位位数。如果设置位的计数为偶数,则偶数和奇数设置位元素的计数保持不变。否则,反转计数并显示。
下面是上述方法的实现:
C++
// C++ Program to count number
// of even and odd set bits
// elements after XOR with a
// given element
#include
using namespace std;
void keep_count(int arr[], int& even,
int& odd, int N)
{
// Store the count of set bits
int count;
for (int i = 0; i < N; i++) {
count = 0;
// Brian Kernighan's algorithm
while (arr[i] != 0) {
arr[i] = (arr[i] - 1) & arr[i];
count++;
}
if (count % 2 == 0)
even++;
else
odd++;
}
return;
}
// Function to solve Q queries
void solveQueries(
int arr[], int n,
int q[], int m)
{
int even_count = 0, odd_count = 0;
keep_count(arr, even_count,
odd_count, n);
for (int i = 0; i < m; i++) {
int X = q[i];
// Store set bits in X
int count = 0;
// Count set bits of X
while (X != 0) {
X = (X - 1) & X;
count++;
}
if (count % 2 == 0) {
cout << even_count << " "
<< odd_count << "\n";
}
else {
cout << odd_count << " "
<< even_count
<< "\n";
}
}
}
// Driver code
int main()
{
int arr[] = { 2, 7, 4, 5, 3 };
int n = sizeof(arr) / sizeof(arr[0]);
int q[] = { 3, 4, 12, 6 };
int m = sizeof(q) / sizeof(q[0]);
solveQueries(arr, n, q, m);
return 0;
}
Java
// Java program to count number
// of even and odd set bits
// elements after XOR with a
// given element
class GFG{
static int even, odd;
static void keep_count(int arr[], int N)
{
// Store the count of set bits
int count;
for(int i = 0; i < N; i++)
{
count = 0;
// Brian Kernighan's algorithm
while (arr[i] != 0)
{
arr[i] = (arr[i] - 1) & arr[i];
count++;
}
if (count % 2 == 0)
even++;
else
odd++;
}
return;
}
// Function to solve Q queries
static void solveQueries(int arr[], int n,
int q[], int m)
{
even = 0;
odd = 0;
keep_count(arr, n);
for(int i = 0; i < m; i++)
{
int X = q[i];
// Store set bits in X
int count = 0;
// Count set bits of X
while (X != 0)
{
X = (X - 1) & X;
count++;
}
if (count % 2 == 0)
{
System.out.print(even + " " +
odd + "\n");
}
else
{
System.out.print(odd + " " +
even + "\n");
}
}
}
// Driver code
public static void main(String[] args)
{
int arr[] = { 2, 7, 4, 5, 3 };
int n = arr.length;
int q[] = { 3, 4, 12, 6 };
int m = q.length;
solveQueries(arr, n, q, m);
}
}
// This code is contributed by amal kumar choubey
Python3
# Python3 program to count number
# of even and odd set bits
# elements after XOR with a
# given element
even = 0
odd = 0
def keep_count(arr, N):
global even
global odd
# Store the count of set bits
for i in range(N):
count = 0
# Brian Kernighan's algorithm
while (arr[i] != 0):
arr[i] = (arr[i] - 1) & arr[i]
count += 1
if (count % 2 == 0):
even += 1
else:
odd += 1
return
# Function to solve Q queries
def solveQueries(arr, n, q, m):
global even
global odd
keep_count(arr, n)
for i in range(m):
X = q[i]
# Store set bits in X
count = 0
# Count set bits of X
while (X != 0):
X = (X - 1) & X
count += 1
if (count % 2 == 0):
print(even, odd)
else:
print(odd, even)
# Driver code
if __name__ == '__main__':
arr = [ 2, 7, 4, 5, 3 ]
n = len(arr)
q = [ 3, 4, 12, 6 ]
m = len(q)
solveQueries(arr, n, q, m)
# This code is contributed by samarth
C#
// C# program to count number
// of even and odd set bits
// elements after XOR with a
// given element
using System;
class GFG{
static int even, odd;
static void keep_count(int []arr, int N)
{
// Store the count of set bits
int count;
for(int i = 0; i < N; i++)
{
count = 0;
// Brian Kernighan's algorithm
while (arr[i] != 0)
{
arr[i] = (arr[i] - 1) & arr[i];
count++;
}
if (count % 2 == 0)
even++;
else
odd++;
}
return;
}
// Function to solve Q queries
static void solveQueries(int []arr, int n,
int []q, int m)
{
even = 0;
odd = 0;
keep_count(arr, n);
for(int i = 0; i < m; i++)
{
int X = q[i];
// Store set bits in X
int count = 0;
// Count set bits of X
while (X != 0)
{
X = (X - 1) & X;
count++;
}
if (count % 2 == 0)
{
Console.Write(even + " " +
odd + "\n");
}
else
{
Console.Write(odd + " " +
even + "\n");
}
}
}
// Driver code
public static void Main()
{
int []arr = { 2, 7, 4, 5, 3 };
int n = arr.Length;
int []q = { 3, 4, 12, 6 };
int m = q.Length;
solveQueries(arr, n, q, m);
}
}
// This code is contributed by Code_Mech
Javascript
输出:
2 3
3 2
2 3
2 3
时间复杂度: O(N * log N)
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