poj 3977 子集

#include<stdio.h>
#include<map>
#include<algorithm>
using namespace std;
#define ll long long
ll a[50];
ll Abs(ll x)
{
    return x<0?-x:x;
}
int main( )
{
  int n;
  while(scanf("%d",&n)!=EOF)
  {    
      if(n==0)
        break;
      for(int i=0 ; i<n ; i++)
       scanf("%lld",&a[i]);
      int n2=n/2;
      pair<ll,int> ans(Abs(a[0]),1);
      map<ll,int>M;
      map<ll,int>::iterator it;
      for(int i=1 ; i<1<<n2 ; i++)
      {
          ll sum=0;int cnt=0;
          for(int j=0 ; j<n2 ; j++)
          {
              if(i>>j&1)
              {
                  sum+=a[j];
                  cnt++;
              }
          }
          ans = min(ans,make_pair(Abs(sum),cnt));
          if(M[sum])
            M[sum]=min(M[sum],cnt);
          else
            M[sum]=cnt;
      }
      for(int i=1 ; i<1<<(n-n2) ; i++)
      {
          ll sum=0;int cnt=0;
          for(int j=0 ; j<n-n2 ; j++)
          {
              if(i>>j&1)
              {
                  sum+=a[j+n2];
                  cnt++;
              }

          }
          ans=min(ans,make_pair(Abs(sum),cnt));
          it = M.lower_bound(-sum);
          if(it != M.end())
            ans = min(ans,make_pair(Abs(sum+it->first),cnt+it->second));
          if(it != M.begin())
            {
                it--;
               ans = min(ans,make_pair(Abs(sum+it->first),cnt+it->second));
            }
            
      }
      printf("%lld %d\n",ans.first,ans.second);
  }
  return 0;

}

#include <iostream>
#include <algorithm>
#include <limits>
#include <map>
using namespace std;
typedef long long LL;
#define MAX_N 36
LL number[MAX_N];
 
LL ll_abs(const LL& x)    // damn it! error C3861: ‘llabs‘: identifier not found
{
    return x >= 0 ? x : -x;
}
 
///////////////////////////SubMain//////////////////////////////////
int main(int argc, char *argv[])
{
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif
    int N;
    while (cin >> N && N)
    {
        for (int i = 0; i < N; ++i)
        {
            cin >> number[i];
        }
        map<LL, int> dp;    // sum的值<->集合元素个数，这里不是绝对值
        pair<LL, int> result(ll_abs(number[0]), 1);    // 最优解
        for (int i = 0; i < 1 << (N / 2); ++i)    // 枚举前 N / 2
        {
            LL sum = 0;
            int num = 0;
            for (int j = 0; j < N / 2; ++j)
            {
                if ((i >> j) & 1)
                {
                    sum += number[j];
                    ++num;
                }
            }
            if (num == 0)
            {
                continue;
            }
            result = min(result, make_pair(ll_abs(sum), num));
            map<LL, int>::iterator it = dp.find(sum);
            if (it != dp.end())
            {
                it->second = min(it->second, num);
            }
            else
            {
                dp[sum] = num;
            }
        }
 
        for (int i = 0; i < 1 << (N - N / 2); ++i)    // 枚举剩下的
        {
            LL sum = 0;
            int num = 0;
            for (int j = 0; j < N - N / 2; ++j)
            {
                if ((i >> j) & 1)
                {
                    sum += number[N / 2 + j];
                    ++num;
                }
            }
            if (num == 0)
            {
                continue;
            }
            result = min(result, make_pair(ll_abs(sum), num));
            // 找寻跟-sum最相近的结果
            map<LL, int>::iterator it = dp.lower_bound(-sum);    // 返回大于或等于-sum的第一个元素位置
            if (it != dp.end())
            {// 可能是该位置
                result = min(result, make_pair(ll_abs(sum + it->first), num + it->second));
            }
            if (it != dp.begin())
            {// 或比该元素小一点点的
                --it;
                result = min(result, make_pair(ll_abs(sum + it->first), num + it->second));
            }
        }
        cout << ll_abs(result.first) << ‘ ‘ << result.second << endl;
    }
#ifndef ONLINE_JUDGE
    fclose(stdin);
    fclose(stdout);
    system("out.txt");
#endif
    return 0;
}