砝码称重
60'
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<bitset> 5 using namespace std; 6 const int maxn=27; 7 const int maxm=2007; 8 bitset<21>bt; 9 int n,m,ans,s; 10 int a[maxn],f[maxn][maxm][3]; 11 bool vis[maxm]; 12 void cunt(int x,int sum,int opt){ 13 if(f[x][sum][opt]==1) return; 14 if(x==n){ 15 vis[sum]=true; 16 return; 17 } 18 if(opt==0){ 19 if(bt[x+1]!=1) cunt(x+1,sum,1); 20 cunt(x+1,sum,0); 21 } 22 else{ 23 if(bt[x+1]!=1) cunt(x+1,sum+a[x+1],1); 24 cunt(x+1,sum+a[x+1],0); 25 } 26 f[x][sum][opt]=1; 27 return; 28 } 29 void prt(int x){ 30 if(x==n+1&&bt.count()==m){ 31 memset(vis,false,sizeof(vis)); 32 memset(f,0,sizeof(f)); 33 cunt(0,0,0); 34 if(bt[0]!=1) cunt(0,0,1); 35 int t=0; 36 for(int i=1;i<=s;i++) if(vis[i]==true) t++; 37 ans=max(ans,t); 38 return; 39 } 40 if(bt.count()>m) return; 41 if(x==n+1&&bt.count()!=m) return; 42 prt(x+1); 43 bt.set(x-1,1); 44 prt(x+1); 45 bt.set(x-1,0); 46 return; 47 } 48 int main(){ 49 cin>>n>>m; 50 for(int i=1;i<=n;i++){cin>>a[i];s+=a[i];} 51 for(int i=1;i<=n;i++) prt(i); 52 cout<<ans<<endl; 53 return 0; 54 }
100'
1 #include<iostream> 2 #include<cstdio> 3 #include<bitset> 4 using namespace std; 5 int n,m,ans; 6 int val[27]; 7 int count(int x){ 8 int cnt=0; 9 for(int i=0;i<=n-1;i++){ 10 if(x&(1<<i)) cnt++; 11 } 12 return cnt; 13 } 14 int main(){ 15 cin>>n>>m; 16 for(int i=0;i<n;i++) cin>>val[i]; 17 for(int i=0;i<=(1<<n)-1;i++){ 18 if(count(i)==n-m){ 19 bitset<2007>bt; 20 bt[0]=1; 21 for(int j=0;j<=(n-1);j++){ 22 if(i&(1<<j)) bt=bt|(bt<<val[j]); 23 } 24 ans=max(ans,(int)bt.count()); 25 } 26 } 27 cout<<ans-1<<endl; 28 return 0; 29 }
