Problem:
Score : 700 points

Problem Statement

There is an integer sequence of length 2^N: A_0, A_1, ..., A_{2^N-1}. (Note that the sequence is 0-indexed.)

For every integer K satisfying 1 \leq K \leq 2^N-1, solve the following problem:

Let i and j be integers. Find the maximum value of A_i + A_j where 0 \leq i < j \leq 2^N-1 and (i or j) \leq K.
Here, or denotes the bitwise OR.

Constraints

1 \leq N \leq 18

1 \leq A_i \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_0 A_1 ... A_{2^N-1}

Output

Print 2^N-1 lines.
In the i-th line, print the answer of the problem above for K=i.

Sample Input 1

2
1 2 3 1

Sample Output 1

3
4
5

For K=1, the only possible pair of i and j is (i,j)=(0,1), so the answer is A_0+A_1=1+2=3.

For K=2, the possible pairs of i and j are (i,j)=(0,1),(0,2).
When (i,j)=(0,2), A_i+A_j=1+3=4. This is the maximum value, so the answer is 4.

For K=3, the possible pairs of i and j are (i,j)=(0,1),(0,2),(0,3),(1,2),(1,3),(2,3) .
When (i,j)=(1,2), A_i+A_j=2+3=5. This is the maximum value, so the answer is 5.

Sample Input 2

3
10 71 84 33 6 47 23 25

Sample Output 2

81
94
155
155
155
155
155

Sample Input 3

4
75 26 45 72 81 47 97 97 2 2 25 82 84 17 56 32

Sample Output 3

101
120
147
156
156
178
194
194
194
194
194
194
194
194
194

Solution in Rust (1.42.0) (judge verdict: Accepted)

#![allow(non_snake_case)]

use proconio::input;
use proconio::fastout;

#[derive(Clone, Debug)]
struct Heap2 {
    x0: i32,
    x1: i32,
}

impl Heap2 {
    fn new() -> Heap2 {
        Heap2 {
            x0: 1,
            x1: -1,
        }
    }

    fn merge(&mut self, h: &Heap2) {
        let mut a = [self.x0, self.x1, h.x0, h.x1];
        a.sort_by(|x, y| y.cmp(x));
        self.x0 = a[0];
        self.x1 = a[1];
    }
}

#[fastout]
fn main() {
    input! {
        N: usize,
        A: [i32; 1 << N],
    }
    let M = 1 << N;
    let mut dp = vec![Heap2::new(); M];
    for i in 0..M {
        dp[i].x0 = A[i];
    }
    for i in 0..N {
        let mask = 1 << i;
        for j in 0..M {
            if j & mask > 0 {
                let tmp = dp[j ^ mask].clone();
                //let tmp = Heap2 { x0: A[j ^ mask], x1: -1 };
                //let tmp = Heap2 { x0: A[j], x1: -1 };
                dp[j].merge(&tmp);
            }
        }
    }
    let mut result = 0;
    for i in 1..M {
        result = std::cmp::max(result, dp[i].x0 + dp[i].x1);
        println!("{}", result);
    }
}