【USACO 1.4.4】母亲的牛奶

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cmath>
 4 #include <cstring>
 5 #include <algorithm>
 6 #include <queue>
 7 const int Max=10000;
 8 #define hash(t) h[t.a][t.b][t.c]
 9 using namespace std;
10 struct State{int a,b,c;}data;
11 bool h[21][21][21],h_2[21];//哈希表 
12 int A,B,C,point=0,ans[Max];
13 void bfs();
14 void check(State t);
15 int main()
16 {
17     //文件操作 
18     freopen("milk3.in","r",stdin);
19     freopen("milk3.out","w",stdout);
20     scanf("%d%d%d",&A,&B,&C);
21     data.a=data.b=0;data.c=C;//初始状态
22     bfs(); 
23     sort(ans,ans+point);
24     for (int i=0;i<point;i++) printf("%d ",ans[i]);
25     return 0;
26 }
27 void bfs()
28 {
29      memset(h,0,sizeof(h));//初始化哈希表
30      memset(h_2,0,sizeof(h_2)); 
31      queue<State>Q;
32      Q.push(data);
33      hash(data)=1;
34      check(data);
35      while (!Q.empty())
36      {
37            State u=Q.front(),v;Q.pop();
38            v=u;
39            //倒满的 
40            if (v.a>=B-v.b) {v.a-=B-v.b;v.b=B;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
41            if (v.b>=A-v.a) {v.b-=A-v.a;v.a=A;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
42            if (v.a>=C-v.c) {v.a-=C-v.c;v.c=C;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
43            if (v.c>=A-v.a) {v.c-=A-v.a;v.a=A;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
44            if (v.c>=B-v.b) {v.c-=B-v.b;v.b=B;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
45            if (v.b>=C-v.c) {v.b-=C-v.c;v.c=C;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
46            //倒不满 
47            if (v.a<B-v.b) {v.b+=v.a;v.a=0;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
48            if (v.b<A-v.a) {v.a+=v.b;v.b=0;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
49            if (v.a<C-v.c) {v.c+=v.a;v.a=0;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
50            if (v.c<A-v.a) {v.a+=v.c;v.c=0;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
51            if (v.c<B-v.b) {v.b+=v.c;v.c=0;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
52            if (v.b<C-v.c) {v.c+=v.b;v.b=0;if (hash(v)==0) {Q.push(v);hash(v)=1;check(v);}}v=u;
53      }
54 }
55 void check(State t)
56 {
57      if (t.a==0 && h_2[t.c]==0)
58      {
59          ans[point++]=t.c;
60          h_2[t.c]=1; 
61      }
62      return;
63 }