给定一个整数N ( N> 1 ),任务是将一个数组[1,N]中的所有整数排列在一个数组中,以使所有元素都不与它们所在的索引(基于1的索引)相同在数组中。
例子:
Input: N = 2
Output: 2 1
Explanation: Only possible arrangement of an array of size 2 is 2 1.
Input: N=5
Output: 2 1 5 3 4
Explanation: One possible arrangement of an array of size 5 is 2 1 5 3 4l.
方法:最简单的想法是将N放置在第一个索引中,并将其余元素[1,N – 1]放置在其余索引中。
下面是上述方法的实现:
C++
// C++ program for the above approach
#include
using namespace std;
// Function to place first N natural
// numbers in an array such that none
// of the values are equal to its indices
void generatepermutation(int N)
{
// Stores the required array
vector answer;
// Place N at the first position
answer.push_back(N);
// Iterate the range [1, N)
for (int i = 1; i < N; i++)
{
// Append elements to the sequence
answer.push_back(i);
}
// Pritn the sequence
for(int i:answer) cout << i << " ";
}
// Driver Code
int main()
{
int N = 4;
generatepermutation(N);
return 0;
}
// This code is contributed by mohit kumar 29.
Java
// Java program for the above approach
import java.util.*;
class GFG
{
// Function to place first N natural
// numbers in an array such that none
// of the values are equal to its indices
static void generatepermutation(int N)
{
// Stores the required array
Vector answer = new Vector();
// Place N at the first position
answer.add(N);
// Iterate the range [1, N)
for (int i = 1; i < N; i++)
{
// Append elements to the sequence
answer.add(i);
}
// Pritn the sequence
for(int i:answer) System.out.print(i+ " ");
}
// Driver Code
public static void main(String[] args)
{
int N = 4;
generatepermutation(N);
}
}
// This code is contributed by 29AjayKumar
Python3
# Python program for the above approach
# Function to place first N natural
# numbers in an array such that none
# of the values are equal to its indices
def generatepermutation(N):
# Stores the required array
answer = []
# Place N at the first position
answer.append(N)
# Iterate the range [1, N)
for i in range(1, N):
# Append elements to the sequence
answer.append(i)
# Pritn the sequence
print(*answer)
# Driver Code
N = 4
generatepermutation(N)
C#
// C# program for the above approach
using System;
class GFG
{
// Function to place first N natural
// numbers in an array such that none
// of the values are equal to its indices
static void generatepermutation(int N)
{
// Stores the required array
int[] answer = new int[N];
// Place N at the first position
answer[0] = N;
// Iterate the range [1, N)
for (int i = 1; i < N; i++)
{
// Append elements to the sequence
answer[i] = i;
}
// Pritn the sequence
foreach(int i in answer) Console.Write(i+ " ");
}
// Driver Code
static public void Main ()
{
int N = 4;
generatepermutation(N);
}
}
// This code is contributed by Dharanendra L V
输出
4 1 2 3
时间复杂度: O(N)
辅助空间: O(1)