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：

 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\n");

85             continue;

86         }

87 

88         ok=dfs(0,m,m,m);

89 

90         printf("%s\n",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\n",ca++,solve()?"Yes":"No");

93     }

94     return 0;

95 }