Rearrange Seats by Rating — Problem Statement & Solution Guide

#include <iostream>
#include <vector>
#include <algorithm>

// Rearrange so that every odd index holds a value greater than any even index.
// If length is odd, the middle element becomes the global maximum.
std::vector<int> rearrangeSeats(std::vector<int>& nums) {
    if (nums.empty()) return {};
    std::sort(nums.begin(), nums.end()); // ascending
    int n = nums.size();
    std::vector<int> res(n);
    int lo = 0, hi = n - 1;
    for (int i = 0; i < n; ++i) {
        if (i % 2 == 0) {
            res[i] = nums[lo++]; // smallest remaining to even positions
        } else {
            res[i] = nums[hi--]; // largest remaining to odd positions
        }
    }
    // If n is odd, the centre index is n/2 and already holds the maximum because
    // the last placed element (when i is odd) is the global maximum.
    return res;
}

int main() {
    int n; std::cin >> n;
    std::vector<int> nums(n);
    for (int i = 0; i < n; ++i) std::cin >> nums[i];
    std::vector<int> ans = rearrangeSeats(nums);
    for (size_t i = 0; i < ans.size(); ++i) {
        std::cout << ans[i];
        if (i + 1 < ans.size()) std::cout << ' ';
    }
    return 0;
}

import java.util.*;

public class Main {
    // Rearrange so that every odd index holds a value greater than any even index.
    // If length is odd, the middle element becomes the global maximum.
    public static int[] rearrangeSeats(int[] nums) {
        if (nums == null || nums.length == 0) return new int[0];
        Arrays.sort(nums); // ascending
        int n = nums.length;
        int[] res = new int[n];
        int lo = 0, hi = n - 1;
        for (int i = 0; i < n; ++i) {
            if (i % 2 == 0) {
                res[i] = nums[lo++]; // smallest to even positions
            } else {
                res[i] = nums[hi--]; // largest to odd positions
            }
        }
        return res;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.hasNextInt() ? sc.nextInt() : 0;
        int[] nums = new int[n];
        for (int i = 0; i < n; ++i) nums[i] = sc.nextInt();
        int[] ans = rearrangeSeats(nums);
        for (int i = 0; i < ans.length; ++i) {
            System.out.print(ans[i]);
            if (i + 1 < ans.length) System.out.print(" ");
        }
    }
}

# Rearrange so that every odd index holds a value greater than any even index.
# If length is odd, the middle element becomes the global maximum.
def rearrange_seats(nums):
    if not nums:
        return []
    nums.sort()  # ascending
    n = len(nums)
    res = [0] * n
    lo, hi = 0, n - 1
    for i in range(n):
        if i % 2 == 0:
            res[i] = nums[lo]
            lo += 1
        else:
            res[i] = nums[hi]
            hi -= 1
    return res

# Example driver (can be removed in production)
if __name__ == "__main__":
    import sys
    data = list(map(int, sys.stdin.read().strip().split()))
    n = data[0] if data else 0
    arr = data[1:1 + n]
    print(' '.join(map(str, rearrange_seats(arr))))

// Rearrange so that every odd index holds a value greater than any even index.
// If length is odd, the middle element becomes the global maximum.
function rearrangeSeats(nums) {
    if (!nums || nums.length === 0) return [];
    nums.sort((a, b) => a - b); // ascending
    const n = nums.length;
    const res = new Array(n);
    let lo = 0, hi = n - 1;
    for (let i = 0; i < n; ++i) {
        if (i % 2 === 0) {
            res[i] = nums[lo++]; // smallest to even positions
        } else {
            res[i] = nums[hi--]; // largest to odd positions
        }
    }
    return res;
}

// Example driver (can be removed in production)
if (require.main === module) {
    const fs = require('fs');
    const input = fs.readFileSync(0, 'utf8').trim().split(/\s+/).map(Number);
    const n = input[0] || 0;
    const arr = input.slice(1, 1 + n);
    console.log(rearrangeSeats(arr).join(' '));
}