UVA_10264_The_Most_Potent_Corner

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <stack>
#include <bitset>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <sstream>
#include <stdlib.h>
#include <cmath>
#define FOR(i,A) for(typeof (A).begin() i = (A).begin() ; i != (A).end() ; i++)
#define debug( x ) cout << #x << " = " << x << endl
#define clr(v,x) memset( v, x , sizeof v )
#define all(x) (x).begin() , (x).end()
#define rall(x) (x).rbegin() , (x).rend()
#define TAM 110

using namespace std;

typedef pair<int,int> ii ;
typedef long long ll ;
typedef long double ld ;
typedef pair<int,ii> pii ;

int N;
int edges[20000];
int sum[20000];

int main() {
    for(;;) {
        if(scanf("%d", &N) != 1) break;
        int num_edges = pow(2, N);
        int max_sum = 0;
        for(int i = 0; i < num_edges; i++)
            scanf("%d", &edges[i]);
        for(int i = 0; i < num_edges; i++) {
            int edge_sum = 0;
            for(int j = 0; j < N; j++) {
                int b = i ^ (1 << j);
                edge_sum += edges[b];
            }
            sum[i] = edge_sum;
        }
        for(int i = 0; i < num_edges; i++) {
            for(int j = 0; j < N; j++) {
                int b = i ^ (1 << j);
                max_sum = max(max_sum, sum[i] + sum[b]);
            }
        }
        printf("%d\n", max_sum);
    }
}