1 //重量太大，用01背包容易超时
2 //数据只有20组。可以用dfs搜索最优解
3 #include<stdio.h>
4 int a[25];
5 int maxs,n,s;
6 void dfs(int,int);
7 int main()
8 {
9 int i;
10 while(~scanf("%d",&n))
11 {
12 for(i=s=0; i<n; ++i)
13 {
14 scanf("%d",a+i);
15 s+=a[i];
16 }
17 maxs=0;
18 dfs(0,0);
19 printf("%d\n",(s-maxs)-maxs);
20 }
21 }
22 void dfs(int x,int sum)
23 {
24 if(x>n)
25 return ;
26 if(sum*2 <= s)
27 {
28 if(sum>maxs)
29 maxs=sum;
30 }
31 else return ;
32
33 dfs(x+1,sum);
34 dfs(x+1,sum+a[x]);
35 }
36
37 //最优解，逆序剪枝
38 #include <stdio.h>
39 #define max(a,b) a>b?a:b
40 int V,ans,n,w[21],sum[21];
41 void dfs(int i,int cnt)
42 {
43 if(i == 0)
44 {
45 ans = max(ans,cnt);
46 return ;
47 }
48 if(ans == V || cnt+sum[i] <= ans) //cut
49 return ;
50 if(cnt+w[i] <= V)
51 dfs(i-1,cnt+w[i]);
52 dfs(i-1,cnt);
53 }
54 int main()
55 {
56 while(~scanf("%d",&n))
57 {
58 ans = 0;
59 for(int i=1;i<=n;i++)
60 {
61 scanf("%d",&w[i]);
62 sum[i] = sum[i-1] + w[i];
63 }
64 V = sum[n]/2;
65 dfs(n,0);
66 printf("%d\n",sum[n]-2*ans);
67 }
68 return 0;
69 }
70
