给定2个正整数N和K以及数组arr [] ,任务是查找是否有可能选择该数组的非空子数组,以使该子数组恰好包含K个偶数整数。
例子:
Input: N = 4, K = 2, arr[] = {1, 2, 4, 5}
Output: Yes
Explanation:
We can select the subarray {2, 4} which contains exactly K = 2 even numbers.
Input: N = 3, K = 3, arr[] = {2, 4, 5}
Output: No
Explanation:
There are only two even numbers. Therefore, we cannot choose a subarray with K = 3 even numbers.
方法:想法是计算数组中的偶数个数。现在可以有3种情况:
- 如果数组中的偶数计数为0 (即,数组中只有奇数),则我们无法选择任何子数组
- 如果数组中的偶数计数≥K ,那么我们可以轻松地选择一个正整数为K个偶数的子数组
- 否则,不可能选择正好为K个偶数整数的子数组
下面是上述方法的实现:
CPP
// C++ program to check if it is possible to
// choose a subarray that contains exactly
// K even integers
#include
using namespace std;
// Function to check if it is possible to
// choose a subarray that contains exactly
// K even integers
void isPossible(int A[], int n, int k)
{
// Variable to store the count of
// even numbers
int countOfTwo = 0;
for (int i = 0; i < n; i++) {
if (A[i] % 2 == 0) {
countOfTwo++;
}
}
// If we have to select 0 even numbers
// but there is all odd numbers in the array
if (k == 0 && countOfTwo == n)
cout << "NO\n";
// If the count of even numbers is greater than
// or equal to K then we can select a
// subarray with exactly K even integers
else if (countOfTwo >= k) {
cout << "Yes\n";
}
// If the count of even numbers is less than K
// then we cannot select any subarray with
// exactly K even integers
else
cout << "No\n";
}
// Driver code
int main()
{
int arr[] = { 1, 2, 4, 5 };
int K = 2;
int N = sizeof(arr) / sizeof(arr[0]);
isPossible(arr, N, K);
return 0;
}
Java
// Java program to check if it is possible to
// choose a subarray that contains exactly
// K even integers
import java.util.*;
class GFG{
// Function to check if it is possible to
// choose a subarray that contains exactly
// K even integers
static void isPossible(int []A, int n, int k)
{
// Variable to store the count of
// even numbers
int countOfTwo = 0;
for (int i = 0; i < n; i++) {
if (A[i] % 2 == 0) {
countOfTwo++;
}
}
// If we have to select 0 even numbers
// but there is all odd numbers in the array
if (k == 0 && countOfTwo == n)
System.out.print("NO");
// If the count of even numbers is greater than
// or equal to K then we can select a
// subarray with exactly K even integers
else if (countOfTwo >= k) {
System.out.print("YES");
}
// If the count of even numbers is less than K
// then we cannot select any subarray with
// exactly K even integers
else
System.out.print("No");
}
// Driver Code
public static void main(String[] args)
{
int []arr = { 1, 2, 4, 5 };
int K = 2;
int n = arr.length;
isPossible(arr, n, K);
}
}
// This code is contributed by shivanisinghss2110
Python3
# Python3 program to check if it is possible to
# choose a subarray that contains exactly
# K even integers
# Function to check if it is possible to
# choose a subarray that contains exactly
# K even integers
def isPossible(A, n, k):
# Variable to store the count of
# even numbers
countOfTwo = 0
for i in range(n):
if (A[i] % 2 == 0):
countOfTwo += 1
# If we have to select 0 even numbers
# but there is all odd numbers in the array
if (k == 0 and countOfTwo == n):
print("NO\n")
# If the count of even numbers is greater than
# or equal to K then we can select a
# subarray with exactly K even integers
elif (countOfTwo >= k):
print("Yes\n")
# If the count of even numbers is less than K
# then we cannot select any subarray with
# exactly K even integers
else:
print("No\n")
# Driver code
if __name__ == '__main__':
arr=[1, 2, 4, 5]
K = 2
N = len(arr)
isPossible(arr, N, K)
# This code is contributed by mohit kumar 29
C#
// C# program to check if it is possible to
// choose a subarray that contains exactly
// K even integers
using System;
class GFG{
// Function to check if it is possible to
// choose a subarray that contains exactly
// K even integers
static void isPossible(int []A, int n, int k)
{
// Variable to store the count of
// even numbers
int countOfTwo = 0;
for (int i = 0; i < n; i++) {
if (A[i] % 2 == 0) {
countOfTwo++;
}
}
// If we have to select 0 even numbers
// but there is all odd numbers in the array
if (k == 0 && countOfTwo == n)
Console.Write("NO");
// If the count of even numbers is greater than
// or equal to K then we can select a
// subarray with exactly K even integers
else if (countOfTwo >= k) {
Console.Write("Yes");
}
// If the count of even numbers is less than K
// then we cannot select any subarray with
// exactly K even integers
else
Console.Write("No");
}
// Driver Code
public static void Main()
{
int []arr = { 1, 2, 4, 5 };
int K = 2;
int n = arr.Length;
isPossible(arr, n, K);
}
}
// This code is contributed by AbhiThakur
Javascript
输出:
Yes
时间复杂度: O(N)