SOJ 1151. 魔板

题目大意：和soj 1150题目大意差不多，不过数据规模变大了，n可能大于10。

解题思路：在1150的基础上作修改，修改状态重复判断的方式。以前是：扫描整个队列，查重；现在是：引入set集合，每个元素只记录up和down的值，进行查重。

代码如下：

  1 #include <iostream>
  2 #include <vector>
  3 #include <string>
  4 #include <set>
  5 using namespace std;
  6
  7 class MagicPlate {
  8 public:
  9     void setUp(int u) {
 10         up = u;
 11     }
 12
 13     void setDown(int d) {
 14         down = d;
 15     }
 16
 17     bool stateEqual(const MagicPlate & mp) {
 18         return up == mp.up && down == mp.down;
 19     }
 20
 21     void reset() {
 22         up = 1234;
 23         down = 8765;
 24         op = NULL;
 25         pre = -1;
 26     }
 27
 28     void operateA() {
 29         int temp = up;
 30         up = down;
 31         down = temp;
 32
 33         op = ‘A‘;
 34     }
 35
 36     void operateB() {
 37         up = up / 10 + up % 10 * 1000;
 38         down = down / 10 + down % 10 * 1000;
 39
 40         op = ‘B‘;
 41     }
 42
 43     void operateC() {
 44         int u = up % 1000 / 10;
 45         int u1 = u / 10;
 46         int u2 = u % 10;
 47         int d = down % 1000 / 10;
 48         int d1 = d / 10;
 49         int d2 = d % 10;
 50
 51         up = up / 1000 * 1000 + d1 * 100 + u1 * 10 + up % 10;
 52         down = down / 1000 * 1000 + d2 * 100 + u2 * 10 + down % 10;
 53
 54         op = ‘C‘;
 55     }
 56
 57     void setPre(int p) {
 58         pre = p;
 59     }
 60
 61     int getPre() {
 62         return pre;
 63     }
 64
 65     char getOp() {
 66         return op;
 67     }
 68
 69     int getUp() {
 70         return up;
 71     }
 72
 73     int getDown() {
 74         return down;
 75     }
 76
 77 private:
 78     int up;
 79     int down;
 80     char op;
 81     int pre;
 82 };
 83
 84
 85
 86 vector<MagicPlate> vt;
 87 set< pair<int, int> > s;
 88 string opStr;
 89 int fp, rp;
 90 int n;
 91
 92 void init() {
 93     opStr = "";
 94     vt.clear();
 95     s.clear();
 96 }
 97
 98 void getGoal(MagicPlate * mp) {
 99     while (mp->getPre() != -1) {
100         opStr.push_back(mp->getOp());
101         mp = &vt[mp->getPre()];
102     }
103 }
104
105 bool visited(MagicPlate *mp) {
106     pair<int, int> p = pair<int, int>(mp->getUp(), mp->getDown());
107
108     if (s.find(p) != s.end()) {
109         return true;
110     } else {
111         return false;
112     }
113     //return false;
114     /*for (int i = 0; i <= fp; i++) {
115         if (vt[i].stateEqual(mp)) {
116             return true;
117         }
118     }
119     return false;*/
120 }
121
122 int main() {
123     while (cin >> n, n != -1) {
124         init();
125         int temp;
126         int up = 0;
127         for (int i = 0; i < 4; i++) {
128             cin >> temp;
129             up = up * 10 + temp;
130         }
131         int down = 0;
132         for (int i = 0; i < 4; i++) {
133             cin >> temp;
134             down = down * 10 + temp;
135         }
136         MagicPlate targetMP;
137         targetMP.setUp(up);
138         targetMP.setDown(down);
139
140         MagicPlate begin;
141         begin.reset();
142         vt.push_back(begin);
143         s.insert(pair<int, int>(begin.getUp(), begin.getDown()));
144         fp = 0;
145         rp = 1;
146
147         if (targetMP.stateEqual(begin)) {
148             cout << 0 << endl;
149             continue;
150         }
151
152         bool flag = false;
153         int step;
154         for (step = 1; step <= n; step++) {
155             int trp = rp;
156             while (fp < trp) {
157                 MagicPlate mp = vt[fp];
158                 MagicPlate mpA(mp);
159                 mpA.operateA();
160                 mpA.setPre(fp);
161                 if (mpA.stateEqual(targetMP)) {
162                     getGoal(&mpA);
163                     flag = true;
164                     break;
165                 } else if (!visited(&mpA)) {
166                     vt.push_back(mpA);
167                     s.insert(pair<int, int>(mpA.getUp(), mpA.getDown()));
168                     rp++;
169                 }
170
171                 MagicPlate mpB(mp);
172                 mpB.operateB();
173                 mpB.setPre(fp);
174                 if (mpB.stateEqual(targetMP)) {
175                     getGoal(&mpB);
176                     flag = true;
177                     break;
178                 } else if (!visited(&mpB)) {
179                     vt.push_back(mpB);
180                     s.insert(pair<int, int>(mpB.getUp(), mpB.getDown()));
181                     rp++;
182                 }
183
184                 MagicPlate mpC(mp);
185                 mpC.operateC();
186                 mpC.setPre(fp);
187                 if (mpC.stateEqual(targetMP)) {
188                     getGoal(&mpC);
189                     flag = true;
190                     break;
191                 } else if (!visited(&mpC)) {
192                     vt.push_back(mpC);
193                     s.insert(pair<int, int>(mpC.getUp(), mpC.getDown()));
194                     rp++;
195                 }
196
197                 fp++;
198             }
199             if (flag) break;
200         }
201
202         if (flag) {
203             cout << step << " " << string(opStr.rbegin(), opStr.rend()) << endl;
204         } else {
205             cout << -1 << endl;
206         }
207     }
208 }