【HDOJ】1732 Push Box

BFS.使用当前结点位置以及三个箱子的位置作为状态。

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cstdlib>
  5 #include <queue>
  6 using namespace std;
  7 
  8 #define MAXN 8
  9 
 10 typedef struct {
 11     int x, y;
 12 } Point_t;
 13 
 14 typedef struct {
 15     Point_t v;
 16     Point_t box[3];
 17     int t;
 18 } Node_t;
 19 
 20 Node_t cur;
 21 bool visit[MAXN][MAXN][MAXN][MAXN][MAXN][MAXN][MAXN][MAXN];
 22 char map[MAXN+5][MAXN+5];
 23 int dir[4][2] = {
 24     {-1,0}, {1,0}, {0,-1}, {0,1}
 25 };
 26 int n, m;
 27 
 28 bool check(int x, int y) {
 29     return x<0 || x>=n || y<0 || y>=m || map[x][y]=='#';
 30 }
 31 
 32 bool getVisit(Node_t a) {
 33     return     visit[a.v.x][a.v.y][a.box[0].x][a.box[0].y][a.box[1].x][a.box[1].y][a.box[2].x][a.box[2].y];
 34 }
 35 
 36 void setVisit(Node_t a) {
 37     visit[a.v.x][a.v.y][a.box[0].x][a.box[0].y][a.box[1].x][a.box[1].y][a.box[2].x][a.box[2].y] = true;
 38 }
 39 
 40 bool isFinish(Node_t a) {
 41     return map[a.box[0].x][a.box[0].y]=='@' && map[a.box[1].x][a.box[1].y]=='@' &&\
 42             map[a.box[2].x][a.box[2].y]=='@';
 43 }
 44 
 45 bool boxCanMove(Node_t a, int d, int id) {
 46     int x = a.v.x + dir[d][0];
 47     int y = a.v.y + dir[d][1];
 48 
 49     if (check(x, y))
 50         return false;
 51 
 52     for (int i=0; i<3; ++i) {
 53         if (i!=id && a.box[i].x==x && a.box[i].y==y)
 54             return false;
 55     }
 56 
 57     return true;
 58 }
 59 
 60 void printNode(Node_t a) {
 61     printf("a.v.x = %d, a.v.y = %d\n", a.v.x, a.v.y);
 62     for (int i=0; i<3; ++i) {
 63         printf("a.box[%d].x = %d, a.box[%d].y = %d\n", i, a.box[0].x, i, a.box[0].y);
 64     }
 65 }
 66 
 67 int bfs() {
 68     queue<Node_t> Q;
 69     int i, j, k;
 70     int x, y;
 71 
 72     memset(visit, false, sizeof(visit));
 73     cur.t = 0;
 74     setVisit(cur);
 75     Q.push(cur);
 76 
 77     while (!Q.empty()) {
 78         Node_t d = Q.front();
 79         Q.pop();
 80 #ifndef ONLINE_JUDGE
 81         printNode(d);
 82 #endif
 83         if (isFinish(d)) {
 84             return d.t;
 85         }
 86 
 87         for (i=0; i<4; ++i) {
 88             x = d.v.x + dir[i][0];
 89             y = d.v.y + dir[i][1];
 90             if (check(x, y))
 91                 continue;
 92             Node_t nd = d;
 93             nd.v.x = x;
 94             nd.v.y = y;
 95             ++nd.t;
 96             for (j=0; j<3; ++j) {
 97                 if (nd.box[j].x == x && nd.box[j].y == y) {
 98                     break;
 99                 }
100             }
101             if (j<3) {
102                 /* next is a box*/
103                 if (boxCanMove(nd, i, j)) {
104                     nd.box[j].x += dir[i][0];
105                     nd.box[j].y += dir[i][1];
106                 } else {
107                     continue;
108                 }
109             }
110 
111             if (!getVisit(nd)) {
112                 setVisit(nd);
113                 Q.push(nd);
114             }
115         }
116     }
117 
118     return -1;
119 }
120 
121 int main() {
122     int i, j, k;
123 
124     #ifndef ONLINE_JUDGE
125         freopen("data.in", "r", stdin);
126     #endif
127 
128     while (scanf("%d %d", &n, &m) != EOF) {
129         k = 0;
130         for (i=0; i<n; ++i) {
131             scanf("%s", map[i]);
132             for (j=0; j<m; ++j) {
133                 if (map[i][j] == 'X') {
134                     cur.v.x = i;
135                     cur.v.y = j;
136                 } else if (map[i][j] == '*') {
137                     cur.box[k].x = i;
138                     cur.box[k].y = j;
139                     ++k;
140                 }
141             }
142         }
143 
144         k = bfs();
145         printf("%d\n", k);
146     }
147 
148     return 0;
149 }

 

posted on 2014-12-13 02:37  Bombe  阅读(211)  评论(0)  编辑  收藏  举报

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