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 PyPy3 (2.4.0) (judge verdict: Accepted)

#!/usr/bin/env python

from collections import deque
import itertools as it
import sys
import math

def func():
    N = int(input())

    A = list(map(int, input().split()))
    P = [[(A[0], 0), (0, 0)] for i in range(2 ** N)]

    for i in range(1, 2 ** N):
        if (A[i], i) > P[i][0]:
            P[i][1] = P[i][0]
            P[i][0] = (A[i], i)
        elif (A[i], i) > P[i][1]:
            P[i][1] = (A[i], i)
        for j in range(N):
            if (i & (1 << j)) == 0:
                index = i + (1 << j)
                for k in range(2):
                    if P[i][k] > P[index][0]:
                        P[index][1] = P[index][0]
                        P[index][0] = P[i][k]
                    elif P[i][k] > P[index][1] and P[i][k] != P[index][0]:
                        P[index][1] = P[i][k]
    ans = 0
    for i in range(1, 2 ** N):
        ans = max(ans, P[i][0][0] + P[i][1][0])
        print(ans)
    #print(P)

func()