Wave_array.cpp

//Given a sorted array arr[] of distinct integers. Sort the array into a wave-like array and return it
//In other words, arrange the elements into a sequence such that arr[1] >= arr[2] <= arr[3] >= arr[4] <= arr[5].....

#include<bits/stdc++.h>
using namespace std;

 // } Driver Code Ends
class Solution{
    public:
    // arr: input array
    // n: size of array
    //Function to sort the array into a wave-like array.
    void convertToWave(vector<int>& arr, int n){
        
        // Your code here
               
        for(int i=1;i<n;i=i+2)
            swap(arr[i],arr[i-1]);
    }
};

// { Driver Code Starts.

int main()
{
    int t,n;
    cin>>t; //Input testcases
    while(t--) //While testcases exist
    {
        cin>>n; //input size of array
        vector<int> a(n); //declare vector of size n
        for(int i=0;i<n;i++)
            cin>>a[i]; //input elements of array
        Solution ob;
        ob.convertToWave(a, n);

        for(int i=0;i<n;i++)
            cout<<a[i]<<" "; //print array
            
        cout<<endl;
    }
}  // } Driver Code Ends