北大poj-2688

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 
  4 #define MAX_MAX 65535
  5 #define MAX_ROOM 25
  6 #define MAX_DIRT 15
  7 #define Q_LEN 10000
  8 
  9 typedef struct
 10 {
 11     int x;
 12     int y;
 13     int step;
 14 }T_Node;
 15 
 16 const int deltax[4] = {-1, 0, 1, 0};
 17 const int deltay[4] = {0, 1, 0, -1};
 18 
 19 T_Node gatDirt[MAX_DIRT];
 20 T_Node queue[Q_LEN];
 21 int gwLen;
 22 int gwWide;
 23 int gwDirtNum = 1;
 24 char gawMap[MAX_ROOM][MAX_ROOM];
 25 int gawDist[MAX_DIRT][MAX_DIRT];
 26 
 27 int BFS(T_Node *ptStart, T_Node *ptEnd)
 28 {
 29     int head = 0;
 30     int tail = 1;
 31     int direction = 0;
 32     char Map[MAX_ROOM][MAX_ROOM];
 33     queue[head] = *ptStart;
 34 
 35     int i,j;
 36     for(j=0; j<gwLen; j++)
 37     {
 38         for(i=0; i<gwWide; i++)
 39         {
 40             Map[j][i] = gawMap[j][i];
 41         }
 42     }
 43 
 44     Map[ptStart->y][ptStart->x] = ‘x‘;
 45     while(head != tail)
 46     {
 47         for(direction=0; direction<4; direction++)
 48         {
 49             if(queue[head].x + deltax[direction] < 0
 50                    || queue[head].x + deltax[direction] >= gwWide
 51                     || queue[head].y + deltay[direction] < 0
 52                      || queue[head].y + deltay[direction] >= gwLen)
 53                 continue;
 54             queue[tail].x = queue[head].x + deltax[direction];
 55             queue[tail].y = queue[head].y + deltay[direction];
 56             if(queue[tail].x == ptEnd->x && queue[tail].y == ptEnd->y)
 57             {
 58                 return queue[head].step + 1;
 59             }
 60             if(Map[queue[tail].y][queue[tail].x] != ‘x‘)
 61             {
 62                 queue[tail].step = queue[head].step + 1;
 63                 Map[queue[tail].y][queue[tail].x] = ‘x‘;
 64                 tail++;
 65             }
 66         }
 67         head++;
 68     }
 69     return -1;
 70 }
 71 
 72 int gawIsCleaned[MAX_DIRT];
 73 int gwBest = MAX_MAX;
 74 
 75 void DFS(int sum, int position, int deep)
 76 {
 77     int k = 0;
 78     int ThisSum = sum;
 79     deep++;
 80     if(deep == gwDirtNum)
 81         if(sum < gwBest)
 82         {
 83             gwBest = sum;
 84             return;
 85         }
 86     for(k=0; k<gwDirtNum; k++)
 87     {
 88         if(gawDist[position][k] ==0 || gawIsCleaned[k] ==1)
 89         {
 90             continue;
 91         }
 92         sum += gawDist[position][k];
 93         if(sum > gwBest)
 94             break;
 95         gawIsCleaned[position] = 1;
 96         DFS(sum, k, deep);
 97         sum = ThisSum;
 98         gawIsCleaned[position] = 0;
 99     }
100     return;
101 }
102 
103 int main(void)
104 {
105     int i,j;
106     while(scanf("%d %d", &gwWide, &gwLen))
107     {
108         getchar();
109         if(gwWide == 0 || gwLen == 0)
110         {
111             return 0;
112         }
113         gwDirtNum = 1;
114         for(j=0; j<gwLen; j++)
115         {
116             for(i=0; i<gwWide; i++)
117             {
118                 scanf("%c", &gawMap[j][i]);
119                 if(gawMap[j][i] == ‘*‘)
120                 {
121                     gatDirt[gwDirtNum].x = i;
122                     gatDirt[gwDirtNum].y = j;
123                     gwDirtNum++;
124                 }
125                 if(gawMap[j][i] == ‘o‘)
126                 {
127                     gatDirt[0].x = i;
128                     gatDirt[0].y = j;
129                 }
130             }
131             getchar();
132         }
133         for(j=0; j<gwDirtNum; j++)
134         {
135             for(i=j+1; i<gwDirtNum; i++)
136             {
137                 gawDist[j][i] = BFS(&gatDirt[i], &gatDirt[j]);
138                 if(gawDist[j][i] == -1)
139                 {
140                     gwBest = 0;
141                     break;
142                 }
143                 if(j != 0) gawDist[i][j] = gawDist[j][i];
144             }
145         }
146 
147         if(gwBest == 0)
148         {
149             gwBest = MAX_MAX;
150             printf("-1\n");
151         }
152         else
153         {
154             gwBest = MAX_MAX;
155             DFS(0, 0, 0);
156             printf("%d\n", gwBest);
157         }
158     }
159     return 0;
160 }