poj 1077 Eight(bfs,dbfs, A*)

代码如下:

bfs:

 1 #include <iostream>
 2 #include <map>
 3 #include <algorithm>
 4 #include <string>
 5 #include <queue>
 6 using namespace std;
 7 typedef long long LL;
 8 
 9 int eight[3][3], xx, xy, dx[]={0,0,-1,1,0}, dy[]={0,1,0,0,-1};
10 char dir[] = "orudl";
11 LL tar;
12 
13 LL encode(){
14     LL s=eight[2][2];
15     for(int i=7; i>=0; --i){
16         s <<=4;
17         s |= eight[i/3][i%3];
18     }
19     return s;
20 }
21 void decode(LL s){
22     for(int i=0; i<9; ++i){
23         eight[i/3][i%3] = s%16;
24         if(s%16 == 0) 
25             xx = i/3, xy = i%3;
26         s >>=4;
27     }
28 }
29 queue<LL> que;
30 map<LL,pair<int,LL> > mp;// pair:d,ps
31 
32 void print(LL s){
33     int d = mp[tar].first;
34     LL ts=s;
35     string ope;
36     while(d!=-1){
37         ope.push_back(dir[d]);
38         ts = mp[ts].second;
39         d = mp[ts].first;
40     }
41     reverse(ope.begin(), ope.end());
42     cout<< ope<< "\n";
43 }
44 void bfs(){
45     mp.clear();
46     LL s = encode(), s2;
47     que.push(s); mp[s] = make_pair(-1,0);
48     while(!que.empty()){
49         s = que.front(); que.pop();
50         for(int i=1; i<5; ++i){
51             decode(s);
52             int r,c;
53             r = xx+dx[i], c = xy+dy[i];
54             if(r<0 || c<0 || r==3 || c==3)
55                 continue;
56             swap(eight[xx][xy], eight[r][c]);
57             s2 = encode();
58             if(mp.find(s2)!=mp.end())
59                 continue;
60             mp[s2] = make_pair(i,s);
61             if(s2==tar){
62                 print(s2);
63                 return ;
64             }
65             else que.push(s2);
66         }
67     }
68 }
69 int main(){
70     std::ios::sync_with_stdio(false);
71     char c;
72     for(int i=0; i<3; ++i){
73         for(int j=0; j<3; ++j){
74             cin>>c;
75             if(c=='x')
76                 eight[i][j]=0, xx = i, xy = j;
77             else 
78                 eight[i][j]= c-'0';
79         }
80     }
81     tar=8;
82     for(int i=7; i>0; --i)
83         tar<<=4, tar |= i;
84     int cnt=0; 
85     for(int i=0; i<9; ++i){
86         for(int pi=0; pi<i; ++pi)
87             if(eight[pi/3][pi%3] && eight[pi/3][pi%3]<eight[i/3][i%3])
88                 cnt++;
89     }
90     if(cnt%2)
91         printf("unsolvable\n");
92     else 
93         bfs();
94     return 0;
95 }

 

dbfs:

 

《poj 1077 Eight(bfs,dbfs, A*)》
《poj 1077 Eight(bfs,dbfs, A*)》

  1 #include <iostream>
  2 #include <map>
  3 #include <algorithm>
  4 #include <string>
  5 #include <queue>
  6 using namespace std;
  7 typedef long long LL;
  8 
  9 int eight[3][3], xx, xy, dx[]={0,0,-1,1,0}, dy[]={0,1,0,0,-1};
 10 char dir[] = "orudl";
 11 
 12 LL encode(){
 13     LL s=eight[2][2];
 14     for(int i=7; i>=0; --i){
 15         s <<=4;
 16         s |= eight[i/3][i%3];
 17     }
 18     return s;
 19 }
 20 void decode(LL s){
 21     for(int i=0; i<9; ++i){
 22         eight[i/3][i%3] = s%16;
 23         if(s%16 == 0) 
 24             xx = i/3, xy = i%3;
 25         s >>=4;
 26     }
 27 }
 28 queue<LL> que[2];
 29 map<LL,pair<int,LL> > mp[2];// pair:d,ps
 30 
 31 void print(LL s){
 32     int d = mp[0][s].first;
 33     LL ts=s;
 34     string ope;
 35     while(d!=-1){
 36         ope.push_back(dir[d]);
 37         ts = mp[0][ts].second;
 38         d = mp[0][ts].first;
 39     }
 40     reverse(ope.begin(), ope.end());
 41     cout<< ope;
 42     ope.clear(), d = mp[1][s].first, ts = s;
 43     while(d!=-1){
 44         ope.push_back(dir[d]);
 45         ts = mp[1][ts].second;
 46         d = mp[1][ts].first;
 47     }
 48     cout << ope << "\n";
 49 }
 50 void expand(int idx){
 51     static int found = 0;
 52     if(found){
 53         while(!que[idx].empty()) que[idx].pop();
 54         return;
 55     }
 56     int len = que[idx].size();
 57     while(len--){
 58         LL s = que[idx].front(), s2; que[idx].pop();
 59         for(int i=1; i<5; ++i){
 60             decode(s);
 61             int r,c;
 62             if(idx==0)
 63                 r = xx+dx[i], c = xy+dy[i];
 64             else 
 65                 r = xx-dx[i], c = xy-dy[i];
 66             if(r<0 || c<0 || r==3 || c==3)
 67                 continue;
 68             swap(eight[xx][xy], eight[r][c]);
 69             s2 = encode();
 70             if(mp[idx].find(s2)!=mp[idx].end())
 71                 continue;
 72             mp[idx][s2] = make_pair(i,s);
 73             if(mp[idx^1].find(s2)!=mp[idx^1].end()){
 74                 print(s2);
 75                 found=1;
 76                 return ;
 77             }
 78             else que[idx].push(s2);
 79         }
 80     }
 81 }
 82 void dbfs(){
 83     mp[0].clear(), mp[1].clear();
 84     LL tar=8;
 85     for(int i=7; i>0; --i)
 86         tar<<=4, tar |= i;
 87     que[1].push(tar); mp[1][tar]=make_pair(-1,0);// 两者相等??
 88     tar = encode();
 89     que[0].push(tar); mp[0][tar] = make_pair(-1,0);
 90     while(!que[0].empty() && !que[1].empty()){
 91         if(que[0].size()<que[1].size())
 92             expand(0);
 93         else expand(1);
 94     }
 95     while(!que[0].empty())
 96         expand(0);
 97     while(!que[1].empty())
 98         expand(1);
 99 }
100 int main(){
101     freopen("C:\\Users\\yyf\\Documents\\CppFiles\\in.txt", "r", stdin);
102     std::ios::sync_with_stdio(false);
103     char c;
104     for(int i=0; i<3; ++i){
105         for(int j=0; j<3; ++j){
106             cin>>c;
107             if(c=='x')
108                 eight[i][j]=0, xx = i, xy = j;
109             else 
110                 eight[i][j]= c-'0';
111         }
112     }
113     int cnt=0; 
114     for(int i=0; i<9; ++i){
115         for(int pi=0; pi<i; ++pi)
116             if(eight[pi/3][pi%3] && eight[pi/3][pi%3]<eight[i/3][i%3])
117                 cnt++;
118     }
119     if(cnt%2)
120         printf("unsolvable\n");
121     else 
122         dbfs();
123     return 0;
124 }

View Code

 

 

 A*:

《poj 1077 Eight(bfs,dbfs, A*)》
《poj 1077 Eight(bfs,dbfs, A*)》

  1 #include <iostream>
  2 #include <map>
  3 #include <algorithm>
  4 #include <string>
  5 #include <queue>
  6 #include <set>
  7 using namespace std;
  8 typedef long long LL;
  9 
 10 int eight[3][3], xx, xy, dx[]={0,-1,1,0}, dy[]={1,0,0,-1};
 11 char dir[] = "rudl";
 12 LL init, tar;
 13 
 14 LL encode(){
 15     LL s=eight[2][2];
 16     for(int i=7; i>=0; --i){
 17         s <<=4;
 18         s |= eight[i/3][i%3];
 19     }
 20     return s;
 21 }
 22 void decode(LL s){
 23     for(int i=0; i<9; ++i){
 24         eight[i/3][i%3] = s%16;
 25         if(s%16 == 0) 
 26             xx = i/3, xy = i%3;
 27         s >>=4;
 28     }
 29 }
 30 class Node {
 31 public:
 32     LL s, ps;
 33     int f,g,h,d;
 34     Node (LL _s=0, LL _ps=0, int _d=-1, int _f=0, int _g=0, int _h=0){
 35         s = _s, ps = _ps, f = _f, g = _g, h = _h, d = _d;
 36     }
 37     int operator<(const Node & b) const {
 38         return this->f < b.f || (this->f==b.f && this->s<b.s);
 39     }
 40 };
 41 
 42 multiset<Node> closed, open;
 43 map<LL, multiset<Node>::iterator> inOpen, inClosed;
 44 
 45 void print(Node nd){
 46     int d = nd.d;
 47     LL ts = nd.s;
 48     string ope;
 49     while(d!=-1){
 50         ope.push_back(dir[d]);
 51         auto itc = inClosed[nd.ps];
 52         nd = *itc;
 53         d = nd.d;
 54     }
 55     reverse(ope.begin(), ope.end());
 56     cout<< ope<< "\n";
 57 }
 58 int hn(LL s){
 59     decode(s);
 60     int cnt=0;
 61     for(int i=0; i<9; ++i){
 62         if(eight[i/3][i%3] != (i+1)%9) cnt++;
 63     }
 64     return cnt;
 65 }
 66 void astar(){
 67     init = encode();
 68     int inith = hn(init);
 69     Node start = Node(init, 0, -1, inith, 0, inith);
 70     open.insert(start);
 71     while(!open.empty()){
 72         Node tn = *open.begin(); inOpen.erase(tn.s); open.erase(tn);
 73         LL ts = tn.s, s2;
 74         int tf = tn.f, tg = tn.g, th = tn.h;
 75         for(int i=0; i<4; ++i){
 76             decode(ts);
 77             int r = xx+dx[i], c=xy+dy[i];
 78             if(r<0 || c<0 || r==3 || c==3) continue;
 79             swap(eight[r][c], eight[xx][xy]);
 80             s2 = encode();
 81             int g = tg+1, h = hn(s2), f = g+h;
 82             Node nd = Node(s2, ts, i, f, g, h);
 83             if(s2 == tar){
 84                 inClosed[tn.s]= closed.insert(tn);
 85                 inClosed[nd.s]= closed.insert(nd);
 86                 print(nd);
 87                 return;
 88             }
 89             auto ito = inOpen.find(s2), itc = inClosed.find(s2);
 90             if(ito == inOpen.end() && itc == inClosed.end()){
 91                 inOpen[nd.s]=open.insert(nd);
 92             }
 93             else if(ito == inOpen.end() && f < itc->second->f){
 94                 closed.erase(itc->second); inClosed.erase(itc); 
 95                 inOpen[nd.s]=open.insert(nd);
 96             }
 97             else if(itc == inClosed.end() && f < ito->second->f){
 98                 // que 里有相同s不同f的node
 99                 open.erase(ito->second), inOpen[nd.s]=open.insert(nd);
100             }
101         }
102         inClosed[tn.s] = closed.insert(tn);
103     }
104 }
105 int main(){
106     std::ios::sync_with_stdio(false);
107     char c;
108     for(int i=0; i<3; ++i){
109         for(int j=0; j<3; ++j){
110             cin>>c;
111             if(c=='x')
112                 eight[i][j]=0, xx = i, xy = j;
113             else 
114                 eight[i][j]= c-'0';
115         }
116     }
117     tar=8;
118     for(int i=7; i>0; --i)
119         tar<<=4, tar |= i;
120     int cnt=0; 
121     for(int i=0; i<9; ++i){
122         for(int pi=0; pi<i; ++pi)
123             if(eight[pi/3][pi%3] && eight[pi/3][pi%3]<eight[i/3][i%3])
124                 cnt++;
125     }
126     if(cnt%2)
127         printf("unsolvable\n");
128     else 
129         astar();
130     return 0;
131 }

View Code

 

    原文作者:Keep_Going
    原文地址: https://www.cnblogs.com/yyf2016/p/5790127.html
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