11059 Maximum Product

題目：http://luckycat.kshs.kh.edu.tw/homework/q11059.htm
觀念：bruteforce (DFS)
難度：luckycat ★

#include <iostream>
#include <string.h>
using namespace std;
int N;
long long arr[20], answer ;
void DFS( int now , long long product ){
    if ( product > answer )
        answer = product;
    if ( now == N )
        return;    
    DFS( now+1 , product * arr[now] );

}
int main(){
    int c = 1;
    while ( cin >> N ){
        for ( int i = 0 ; i < N ; i++ )
            cin >> arr[i];    
        answer = 0;
        for ( int str = 0 ; str < N ; str++ )
            DFS( str+1 , arr[str] );

        cout << "Case #" << c++ << ": The maximum product is " << answer << "." << endl;
        cout << endl;
    }

    return 0;    
}

解題示意