poj 3414 Pots bfs+模拟 

  1 #include<iostream> 
  2 #include<cstring>
  3 #define fillA 1
  4 #define pourAB 2
  5 #define dropA 3
  6 #define fillB 4
  7 #define pourBA 5
  8 #define dropB 6
  9 
 10 #define N 10000
 11 
 12 using namespace std;
 13 int vis[105][105];
 14 class node
 15 {
 16 public:
 17    int A, B;
 18    int dir;
 19    node()
 20    {
 21       A=0;
 22       B=0;
 23    }
 24 };
 25 
 26 int a, b, c, tot;
 27 node q[N];
 28 int pre[N];
 29 
 30 void printPath(int index)
 31 {
 32    if(index==0)
 33    {
 34        cout<<tot<<endl; 
 35        return ;
 36    } 
 37    ++tot;
 38    printPath(pre[index]);
 39    switch(q[index].dir)
 40    {
 41       case 1:
 42            cout<<"FILL(1)";
 43            break;
 44       case 2:
 45            cout<<"POUR(1,2)";
 46            break;
 47       case 3:
 48            cout<<"DROP(1)";
 49            break;
 50       case 4:
 51            cout<<"FILL(2)";
 52            break;
 53       case 5:
 54            cout<<"POUR(2,1)";
 55            break;
 56       case 6:
 57            cout<<"DROP(2)";
 58            break;
 59    }
 60    cout<<endl;
 61 }
 62 
 63 int bfs()
 64 {
 65    int head=0, rear=1, r;
 66    node cur, next;
 67    memset(vis, 0, sizeof(vis));
 68    pre[0]=0;
 69    vis[0][0]=1;
 70    while(head<rear)
 71    {
 72        cur=q[head];
 73        if(cur.A==c || cur.B==c)
 74        {
 75              printPath(head);
 76              return 1;
 77        }
 78        next=cur;
 79        if(!vis[a][cur.B])//将 A 装满 
 80        {
 81              next.A=a;
 82              next.dir=fillA;
 83              pre[rear]=head;
 84              vis[a][cur.B]=1;
 85              q[rear++]=next;
 86        }
 87        if(!vis[0][cur.B])//将 A 倒掉 
 88        {
 89              next.A=0;
 90              next.dir=dropA;
 91              pre[rear]=head;
 92              vis[0][cur.B]=1;
 93              q[rear++]=next;
 94        }
 95        r=b-cur.B;
 96        next.dir=pourAB;
 97        if(r>cur.A && !vis[0][cur.B+cur.A])//将A 倒向 B 
 98        {
 99              next.A=0;
100              next.B=cur.B+cur.A;
101              pre[rear]=head;
102              q[rear++]=next;
103              vis[0][cur.B+cur.A]=1;
104        }
105        else if(r<=cur.A && !vis[cur.A-r][cur.B+r])
106        {
107              next.A=cur.A-r;
108              next.B=cur.B+r;
109              pre[rear]=head;
110              q[rear++]=next;
111              vis[cur.A-r][cur.B+r]=1;
112        }
113        
114        next=cur;//开始错在这里了， 忘记了从新给next赋值了
115        if(!vis[cur.A][b])//将 B 装满 
116        {
117              next.B=b;
118              next.dir=fillB;
119              pre[rear]=head;
120              q[rear++]=next;
121              vis[cur.A][b]=1;
122        }
123        if(!vis[cur.A][0])//将 B 倒掉 
124        {
125              next.B=0;
126              next.dir=dropB;
127              pre[rear]=head;
128              q[rear++]=next;
129              vis[cur.A][0]=1;
130        }
131        r=a-cur.A;
132        next.dir=pourBA;
133        if(r>cur.B && !vis[cur.B+cur.A][0])//将B 倒向 A
134        {
135              next.B=0;
136              next.A=cur.B+cur.A;
137              pre[rear]=head;
138              q[rear++]=next;
139              vis[cur.B+cur.A][0]=1;
140        }
141        else if(r<=cur.B && !vis[cur.A+r][cur.B-r])
142        {
143              next.A=cur.A+r;
144              next.B=cur.B-r;
145              pre[rear]=head;
146              q[rear++]=next;
147              vis[cur.A+r][cur.B-r]=1;
148        }
149       ++head;  
150    }
151    return 0;
152 }
153 
154 int main()
155 {
156    while(cin>>a>>b>>c)
157    {
158       tot=0;
159       if(c>a && c>b)
160       {
161          cout<<"impossible"<<endl;
162          continue;
163       }
164       if(!bfs())
165          cout<<"impossible"<<endl;
166    }
167    return 0;
168 }

 

posted @ 2014-06-11 22:00  hjzqyx  阅读(249)  评论(0)  编辑  收藏  举报