BNUOJ-29358 Come to a spring outing 搜索,DP

　　题目链接：http://www.bnuoj.com/bnuoj/problem_show.php?pid=29358

　　状态虽然很多，但是非常稀疏，dfs搜索然后剪下枝。。

　　或者DP，f[i][j][k]表示前 i 个物品能否到达第一个背包和第二个背包容量分别为 j 和 k 的状态，然后判断第3个背包是否能装下剩下的。f[i][j][k]=f[i-1][j][k] | f[i-1][j-v[i]][k] | f[i-1][j][k-v[i]]..

　　搜索：

 //STATUS:C++_AC_10MS_1308KB
 #include <functional>
 #include <algorithm>
 #include <iostream>
 //#include <ext/rope>
 #include <fstream>
 #include <sstream>
 #include <iomanip>
 #include <numeric>
 #include <cstring>
 #include <cassert>
 #include <cstdio>
 #include <string>
 #include <vector>
 #include <bitset>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <ctime>
 #include <list>
 #include <set>
 //#include <map>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,102400000")
 //using namespace __gnu_cxx;
 //define
 #define pii pair<int,int>
 #define mem(a,b) memset(a,b,sizeof(a))
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define PI acos(-1.0)
 //typedef
 //typedef __int64 LL;
 //typedef unsigned __int64 ULL;
 //const
 const int N=;
 const int INF=0x3f3f3f3f;
 const int MOD=,STA=;
 //const LL LNF=1LL<<60;
 const double EPS=1e-;
 const double OO=1e15;
 const int dx[]={-,,,};
 const int dy[]={,,,-};
 const int day[]={,,,,,,,,,,,,};
 //Daily Use ...
 inline int sign(double x){return (x>EPS)-(x<-EPS);}
 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
 template<class T> inline T Min(T a,T b){return a<b?a:b;}
 template<class T> inline T Max(T a,T b){return a>b?a:b;}
 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
 //End

 int v[N];
 int T,n,m;

 int dfs(int d,int a,int b,int c)
 {
     if(d==n)return ;
     if(a>=v[d] && dfs(d+,a-v[d],b,c))return ;
     if(b>=v[d] && dfs(d+,a,b-v[d],c))return ;
     if(c>=v[d] && dfs(d+,a,b,c-v[d]))return ;
     return ;
 }

 int main(){
  //   freopen("in.txt","r",stdin);
     int i,j,ca=,ok,sum;
     scanf("%d",&T);
     while(T--)
     {
         scanf("%d%d",&n,&m);
         sum=;
         for(i=;i<n;i++){
             scanf("%d",&v[i]);
             sum+=v[i];
         }
         printf("Case %d: ",ca++);
         if(m*m*m<sum){
             printf("No\n");
             continue;
         }

         ok=dfs(,m,m,m);

         printf("%s\n",ok?"Yes":"No");
     }
     return ;
 }

　　

　　DP：

 //STATUS:C++_AC_730MS_24308KB
 #include <functional>
 #include <algorithm>
 #include <iostream>
 //#include <ext/rope>
 #include <fstream>
 #include <sstream>
 #include <iomanip>
 #include <numeric>
 #include <cstring>
 #include <cassert>
 #include <cstdio>
 #include <string>
 #include <vector>
 #include <bitset>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <ctime>
 #include <list>
 #include <set>
 //#include <map>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,102400000")
 //using namespace __gnu_cxx;
 //define
 #define pii pair<int,int>
 #define mem(a,b) memset(a,b,sizeof(a))
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define PI acos(-1.0)
 //typedef
 typedef long long LL;
 typedef unsigned long long ULL;
 //const
 const int N=;
 const int INF=0x3f3f3f3f;
 const int MOD=,STA=;
 const LL LNF=1LL<<;
 const double EPS=1e-;
 const double OO=1e15;
 const int dx[]={-,,,};
 const int dy[]={,,,-};
 const int day[]={,,,,,,,,,,,,};
 //Daily Use ...
 inline int sign(double x){return (x>EPS)-(x<-EPS);}
 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
 template<class T> inline T Min(T a,T b){return a<b?a:b;}
 template<class T> inline T Max(T a,T b){return a>b?a:b;}
 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
 //End

 int f[N][][],v[N];
 int T,n,m,sum;

 bool solve()
 {
     int i,j,k;
     mem(f,);
     f[][][]=;
     for(i=;i<=n;i++){
         for(j=;j<=m;j++){
             for(k=;k<=m;k++){
                 f[i][j][k]|=f[i-][j][k];
                 if(j>=v[i])f[i][j][k]|=f[i-][j-v[i]][k];
                 if(k>=v[i])f[i][j][k]|=f[i-][j][k-v[i]];
                 if(f[i][j][k] && sum-j-k<=m)return true;
             }
         }
     }
     return false;
 }

 int main(){
  //   freopen("in.txt","r",stdin);
     int i,j,ca=;
     scanf("%d",&T);
     while(T--)
     {
         scanf("%d%d",&n,&m);
         sum=;
         for(i=;i<=n;i++){
             scanf("%d",&v[i]);
             sum+=v[i];
         }

         printf("Case %d: %s\n",ca++,solve()?"Yes":"No");
     }
     return ;
 }