bzoj1673[Usaco2005 Dec]Scales 天平*

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define inc(i,j,k) for(int i=j;i<=k;i++)
 5 #define maxn 1010
 6 using namespace std;
 7 
 8 inline int read(){
 9     char ch=getchar(); int f=1,x=0;
10     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
11     while(ch>=‘0‘&&ch<=‘9‘)x=x*10+ch-‘0‘,ch=getchar();
12     return f*x;
13 }
14 int n,a[maxn],c,ans; long long sm[maxn];
15 void dfs(int x,int y){
16     if(sm[x]+y<=ans)return; ans=max(ans,y); for(int i=x;i>=1;i--)if(y+a[i]<=c)dfs(i-1,y+a[i]);
17 }
18 int main(){
19     n=read(); c=read();
20     inc(i,1,n)a[i]=read(),sm[i]=sm[i-1]+a[i]; while(a[n]>c)n--; dfs(n,0); printf("%d",ans);
21 }