奇偶序列中的第 k 个数字
给定两个数字 n 和 k，在由 n 组成的奇-偶序列中找到第 k 个数字。奇-偶序列首先包含从 1 到 n 的所有奇数，然后包含集合 1 到 n 中的所有偶数。
Examples :
Input : n = 5, k = 3
Output : 5
In this example, the Odd-Even is
{1, 3, 5, 2, 4}.
The third number in sequence is 5.
天真方法:
第一种方法是简单地制作一个奇偶序列，然后在其中找到第 k 个元素。
C++
// CPP program to find k-th
// element in the Odd-Even
// sequence.
#include <bits/stdc++.h>
using namespace std;
int findK(int n, int k)
{
vector<long> a;
// insert all the odd
// numbers from 1 to n.
for (int i = 1; i < n; i++)
if (i % 2 == 1)
a.push_back(i);
// insert all the even
// numbers from 1 to n.
for (int i = 1; i < n; i++)
if (i % 2 == 0)
a.push_back(i);
return (a[k - 1]);
}
// Driver code
int main()
{
long n = 10, k = 3;
cout << findK(n, k) << endl;
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find k-th
// element in the Odd-Even
// sequence.
import java.util.*;
class GFG{
static int findK(int n, int k)
{
ArrayList<Integer> a = new ArrayList<Integer>(n);
// insert all the odd
// numbers from 1 to n.
for (int i = 1; i < n; i++)
if (i % 2 == 1)
a.add(i);
// insert all the even
// numbers from 1 to n.
for (int i = 1; i < n; i++)
if (i % 2 == 0)
a.add(i);
return (a.get(k - 1));
}
// Driver code
public static void main(String[] args)
{
int n = 10, k = 3;
System.out.println(findK(n, k));
}
}
// This code is contributed by mits
Python 3
# Python3 code to find
# k-th element in the
# Odd-Even sequence.
def findK (n, k ):
a = list()
# insert all the odd
# numbers from 1 to n.
i = 1
while i < n:
a.append(i)
i = i + 2
# insert all the even
# numbers from 1 to n.
i = 2
while i < n:
a.append(i)
i = i + 2
return (a[k - 1])
# Driver code
n = 10
k = 3
print(findK(n, k))
# This code is contributed
# by "Sharad_Bhardwaj".
C
// C# program to find k-th
// element in the Odd-Even
// sequence.
using System;
using System.Collections;
class GFG{
static int findK(int n, int k)
{
ArrayList a = new ArrayList(n);
// insert all the odd
// numbers from 1 to n.
for (int i = 1; i < n; i++)
if (i % 2 == 1)
a.Add(i);
// insert all the even
// numbers from 1 to n.
for (int i = 1; i < n; i++)
if (i % 2 == 0)
a.Add(i);
return (int)(a[k - 1]);
}
// Driver code
static void Main()
{
int n = 10, k = 3;
Console.WriteLine(findK(n, k));
}
}
// This code is contributed by mits
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to find k-th
// element in the Odd-Even
// sequence.
function findK($n, $k)
{
$a;
$index = 0;
// insert all the odd
// numbers from 1 to n.
for ($i = 1; $i < $n; $i++)
if ($i % 2 == 1)
$a[$index++] = $i;
// insert all the even
// numbers from 1 to n.
for ($i = 1; $i < $n; $i++)
if ($i % 2 == 0)
$a[$index++] = $i;
return ($a[$k - 1]);
}
// Driver code
$n = 10;
$k = 3;
echo findK($n, $k);
// This code is contributed by mits.
?>
java 描述语言
<script>
// Javascript program to find k-th
// element in the Odd-Even
// sequence.
function findK(n, k)
{
let a = [];
// insert all the odd
// numbers from 1 to n.
for (let i = 1; i < n; i++)
if (i % 2 == 1)
a.push(i);
// insert all the even
// numbers from 1 to n.
for (let i = 1; i < n; i++)
if (i % 2 == 0)
a.push(i);
return (a[k - 1]);
}
let n = 10, k = 3;
document.write(findK(n, k));
// This code is contributed by mukesh07.
</script>
输出:
5
上述方法的时间复杂度为 O(n)，对于 O(1)方法，请阅读这里讨论的方法。
版权属于：月萌API www.moonapi.com，转载请注明出处
