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：
1 //STATUS:C++_AC_10MS_1308KB 2 #include <functional> 3 #include <algorithm> 4 #include <iostream> 5 //#include <ext/rope> 6 #include <fstream> 7 #include <sstream> 8 #include <iomanip> 9 #include <numeric> 10 #include <cstring> 11 #include <cassert> 12 #include <cstdio> 13 #include <string> 14 #include <vector> 15 #include <bitset> 16 #include <queue> 17 #include <stack> 18 #include <cmath> 19 #include <ctime> 20 #include <list> 21 #include <set> 22 //#include <map> 23 using namespace std; 24 //#pragma comment(linker,"/STACK:102400000,102400000") 25 //using namespace __gnu_cxx; 26 //define 27 #define pii pair<int,int> 28 #define mem(a,b) memset(a,b,sizeof(a)) 29 #define lson l,mid,rt<<1 30 #define rson mid+1,r,rt<<1|1 31 #define PI acos(-1.0) 32 //typedef 33 //typedef __int64 LL; 34 //typedef unsigned __int64 ULL; 35 //const 36 const int N=35; 37 const int INF=0x3f3f3f3f; 38 const int MOD=100000,STA=8000010; 39 //const LL LNF=1LL<<60; 40 const double EPS=1e-8; 41 const double OO=1e15; 42 const int dx[4]={-1,0,1,0}; 43 const int dy[4]={0,1,0,-1}; 44 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31}; 45 //Daily Use ... 46 inline int sign(double x){return (x>EPS)-(x<-EPS);} 47 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;} 48 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;} 49 template<class T> inline T lcm(T a,T b,T d){return a/d*b;} 50 template<class T> inline T Min(T a,T b){return a<b?a:b;} 51 template<class T> inline T Max(T a,T b){return a>b?a:b;} 52 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);} 53 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);} 54 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));} 55 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));} 56 //End 57 58 int v[N]; 59 int T,n,m; 60 61 int dfs(int d,int a,int b,int c) 62 { 63 if(d==n)return 1; 64 if(a>=v[d] && dfs(d+1,a-v[d],b,c))return 1; 65 if(b>=v[d] && dfs(d+1,a,b-v[d],c))return 1; 66 if(c>=v[d] && dfs(d+1,a,b,c-v[d]))return 1; 67 return 0; 68 } 69 70 int main(){ 71 // freopen("in.txt","r",stdin); 72 int i,j,ca=1,ok,sum; 73 scanf("%d",&T); 74 while(T--) 75 { 76 scanf("%d%d",&n,&m); 77 sum=0; 78 for(i=0;i<n;i++){ 79 scanf("%d",&v[i]); 80 sum+=v[i]; 81 } 82 printf("Case %d: ",ca++); 83 if(m*m*m<sum){ 84 printf("No "); 85 continue; 86 } 87 88 ok=dfs(0,m,m,m); 89 90 printf("%s ",ok?"Yes":"No"); 91 } 92 return 0; 93 }
DP：
1 //STATUS:C++_AC_730MS_24308KB 2 #include <functional> 3 #include <algorithm> 4 #include <iostream> 5 //#include <ext/rope> 6 #include <fstream> 7 #include <sstream> 8 #include <iomanip> 9 #include <numeric> 10 #include <cstring> 11 #include <cassert> 12 #include <cstdio> 13 #include <string> 14 #include <vector> 15 #include <bitset> 16 #include <queue> 17 #include <stack> 18 #include <cmath> 19 #include <ctime> 20 #include <list> 21 #include <set> 22 //#include <map> 23 using namespace std; 24 //#pragma comment(linker,"/STACK:102400000,102400000") 25 //using namespace __gnu_cxx; 26 //define 27 #define pii pair<int,int> 28 #define mem(a,b) memset(a,b,sizeof(a)) 29 #define lson l,mid,rt<<1 30 #define rson mid+1,r,rt<<1|1 31 #define PI acos(-1.0) 32 //typedef 33 typedef long long LL; 34 typedef unsigned long long ULL; 35 //const 36 const int N=35; 37 const int INF=0x3f3f3f3f; 38 const int MOD=100000,STA=8000010; 39 const LL LNF=1LL<<60; 40 const double EPS=1e-8; 41 const double OO=1e15; 42 const int dx[4]={-1,0,1,0}; 43 const int dy[4]={0,1,0,-1}; 44 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31}; 45 //Daily Use ... 46 inline int sign(double x){return (x>EPS)-(x<-EPS);} 47 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;} 48 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;} 49 template<class T> inline T lcm(T a,T b,T d){return a/d*b;} 50 template<class T> inline T Min(T a,T b){return a<b?a:b;} 51 template<class T> inline T Max(T a,T b){return a>b?a:b;} 52 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);} 53 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);} 54 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));} 55 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));} 56 //End 57 58 int f[N][410][410],v[N]; 59 int T,n,m,sum; 60 61 bool solve() 62 { 63 int i,j,k; 64 mem(f,0); 65 f[0][0][0]=1; 66 for(i=1;i<=n;i++){ 67 for(j=0;j<=m;j++){ 68 for(k=0;k<=m;k++){ 69 f[i][j][k]|=f[i-1][j][k]; 70 if(j>=v[i])f[i][j][k]|=f[i-1][j-v[i]][k]; 71 if(k>=v[i])f[i][j][k]|=f[i-1][j][k-v[i]]; 72 if(f[i][j][k] && sum-j-k<=m)return true; 73 } 74 } 75 } 76 return false; 77 } 78 79 int main(){ 80 // freopen("in.txt","r",stdin); 81 int i,j,ca=1; 82 scanf("%d",&T); 83 while(T--) 84 { 85 scanf("%d%d",&n,&m); 86 sum=0; 87 for(i=1;i<=n;i++){ 88 scanf("%d",&v[i]); 89 sum+=v[i]; 90 } 91 92 printf("Case %d: %s ",ca++,solve()?"Yes":"No"); 93 } 94 return 0; 95 }