BZOJ2252 [2010Beijing wc]矩阵距离

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstdlib>
 4 #include <cstring>
 5 #include <queue>
 6 
 7 const int MAXN = 1000 + 10;
 8 const int MAXM = 1000 + 10;
 9 const int dx[4] = {0,0,1,-1};
10 const int dy[4] = {1,-1,0,0};
11 
12 inline void read(int &x)
13 {
14     x = 0;char ch = getchar(), c = ch;
15     while(ch < ‘0‘ || ch > ‘9‘)c = ch, ch = getchar();
16     while(ch <= ‘9‘ &&ch >= ‘0‘)x = x * 10 + ch - ‘0‘, ch = getchar();
17     if(c == ‘-‘)x = -x;
18 }
19 
20 int n,m,g[MAXN][MAXM],ans[MAXN][MAXM],b[MAXN][MAXM];
21 char s[MAXM];
22 
23 struct Node
24 {
25     int x, y;
26     Node(int xx, int yy){x = xx;y = yy;}
27     Node(){}
28 };
29 
30 std::queue<Node> q;
31 
32 void bfs()
33 {
34     register Node tmp;
35     register int xx, yy;
36     while(q.size())
37     {
38         tmp = q.front();q.pop();
39         for(register int i = 0;i < 4;++ i)
40         {
41             xx = tmp.x + dx[i], yy = tmp.y + dy[i];
42             if(xx < 1 || yy < 1 || xx > n || yy > m || b[xx][yy])continue;
43             ans[xx][yy] = ans[tmp.x][tmp.y] + 1;
44             b[xx][yy] = 1;
45             q.push(Node(xx, yy));
46         }
47     }
48 }
49 
50 int main()
51 {
52     read(n), read(m);
53     for(register int i = 1;i <= n;++ i)
54         {
55             scanf("%s", s + 1);
56             for(register int j = 1;j <= m;++ j)
57             {
58                 g[i][j] = s[j] - ‘0‘;
59                 if(g[i][j])
60                 {
61                     b[i][j] = 1;
62                     q.push(Node(i,j));
63                 }
64             }
65         }
66     bfs();
67     for(register int i = 1;i <= n;++ i)
68     {
69         for(register int j = 1;j <= m;++ j)
70             printf("%d ", ans[i][j]);
71         putchar(‘\n‘);
72     }
73     return 0;
74 }