字典序最小交替数组
给定一个由不同元素组成的数组arr[] ，任务是重新排列数组，使其按字典顺序排列最小，格式为arr[0] > arr[1] < arr[2] > arr[3] < ...
例子：
Input: arr[] = {3, 2, 1, 4, 5}
Output: 2 1 4 3 5
Input: arr[] = {10, 22}
Output: 22 10
方法：为了得到字典序最小的数组，我们可以选择最小的元素作为第一个元素，但这不会满足第一个元素必须严格大于第二个元素的条件。
现在，次佳选择是从数组中选择第二个最小值，唯一小于它的元素是将成为数组第二个元素的最小元素。
对数组的其余元素应用相同的过程，选择剩余元素的第二个最小值，然后为每两个连续位置选择最小值，这可以通过首先对给定数组进行排序然后每两个连续元素交换来获得。
下面是上述方法的实现：
C++
// C++ implementation of the approach
#include
using namespace std;
// Function to print the
// contents of an array
void printArr(int arr[], int n)
{
for (int i = 0; i < n; i++) {
cout << arr[i] << " ";
}
}
// Function to find the lexicographically
// smallest alternating array
void smallestArr(int arr[], int n)
{
// Sort the array
sort(arr, arr + n);
// Swap every two consecutive elements
for (int i = 0; i + 1 < n; i = i + 2) {
swap(arr[i], arr[i + 1]);
}
// Print the re-arranged array
printArr(arr, n);
}
// Driver code
int main()
{
int arr[] = { 3, 2, 1, 4, 5 };
int n = sizeof(arr) / sizeof(arr[0]);
smallestArr(arr, n);
return 0;
} Java
// Java implementation of the approach
import java.util.Arrays;
class GFG
{
// Function to print the
// contents of an array
static void printArr(int[] arr, int n)
{
for (int i = 0; i < n; i++)
System.out.print(arr[i] + " ");
}
// Function to find the lexicographically
// smallest alternating array
static void smallestArr(int[] arr, int n)
{
// Sort the array
Arrays.sort(arr);
// Swap every two consecutive elements
for (int i = 0; i + 1 < n; i = i + 2)
{
int temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
// Print the re-arranged array
printArr(arr, n);
}
// Driver code
public static void main(String[] args)
{
int[] arr = { 3, 2, 1, 4, 5 };
int n = arr.length;
smallestArr(arr, n);
}
}
// This code is contributed by
// sanjeev2552Python3
# Python3 implementation of the approach
# Function to print the
# contents of an array
def printArr(arr, n):
for i in range(n):
print(arr[i], end = " ");
# Function to find the lexicographically
# smallest alternating array
def smallestArr(arr, n):
# Sort the array
arr.sort();
# Swap every two consecutive elements
for i in range(0, n - 1, 2):
temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
# Print the re-arranged array
printArr(arr, n);
# Driver code
if __name__ == '__main__':
arr = [ 3, 2, 1, 4, 5 ];
n = len(arr);
smallestArr(arr, n);
# This code contributed by Rajput-JiC#
// C# implementation of the approach
using System;
class GFG
{
// Function to print the
// contents of an array
static void printArr(int[] arr, int n)
{
for (int i = 0; i < n; i++)
Console.Write(arr[i] + " ");
}
// Function to find the lexicographically
// smallest alternating array
static void smallestArr(int[] arr, int n)
{
// Sort the array
Array.Sort(arr);
// Swap every two consecutive elements
for (int i = 0; i + 1 < n; i = i + 2)
{
int temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
// Print the re-arranged array
printArr(arr, n);
}
// Driver code
public static void Main(String[] args)
{
int[] arr = { 3, 2, 1, 4, 5 };
int n = arr.Length;
smallestArr(arr, n);
}
}
// This code is contributed by 29AjayKumarPHP
Javascript
// javascript implementation of the approach
// Function to print the
// contents of an array
function printArr(arr, n)
{
for (var i = 0; i < n; i++)
document.write(arr[i] + " ");
}
// Function to find the lexicographically
// smallest alternating array
function smallestArr( arr, n)
{
// Sort the array
arr.sort();
// Swap every two consecutive elements
for (var i = 0; i + 1 < n; i = i + 2)
{
var temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
// Print the re-arranged array
printArr(arr, n);
}
// Driver code
var arr = [ 3, 2, 1, 4, 5 ] ;
var n = arr.length;
smallestArr(arr, n);
// This code is contributed by bunnyram19.输出：
2 1 4 3 5如果您希望与专家一起参加现场课程，请参阅DSA 现场工作专业课程和学生竞争性编程现场课程。