SOJ 1150.简单魔板

题目大意：中文题面，可直接看题目理解。

数据结构：

MagicPlate:

　　int up : 代表魔板上层的状态

　　int down : 代表魔板下层的状态

　　char op : 表示当前魔板状态是通过哪种操作('A'、'B'、'C')获得的

　　int pre : 代表通过op操作获得当前魔板状态的魔板状态（也即父节点）

vector<MagicPlate> vt : 模拟队列

解题思路：通过广搜对三叉树进行遍历。若发现重复状态，适当剪枝以降低复杂度。

代码如下：

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

 

posted @ 2015-09-29 23:34  MchCyLh  阅读(376)  评论(0)  编辑  收藏  举报