loj 1337

题目链接:http://lightoj.com/volume_showproblem.php?problem=1337

思路:对于搜过的区域进行标记,如果要求的点落在已经搜过的区域,那么直接取出来即可,否则,就dfs一下。

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <algorithm>
 6 #include <queue>
 7 using namespace std;
 8 
 9 const int MAXN = (500 + 50);
10 int n, m, Q, _count, cnt;
11 char map[MAXN][MAXN];
12 int mark[MAXN][MAXN];
13 vector<int >ans;
14 int dir[4][2] = { { -1, 0 }, { 1, 0 }, { 0, -1 }, { 0, 1} };
15 
16 void dfs(int x, int y)
17 {
18     mark[x][y] = _count;
19     if (map[x][y] == 'C') cnt++;
20     for (int i = 0; i < 4; i++) {
21         int xx = x + dir[i][0];
22         int yy = y + dir[i][1];
23         if (xx >= 0 && xx < n && yy >= 0 && yy < m && map[xx][yy] != '#') {
24             if (mark[xx][yy] == -1)dfs(xx, yy);
25         }
26     }
27 }
28 
29 
30 int main()
31 {
32     int _case, t = 1;
33     scanf("%d", &_case);
34     while (_case--) {
35         scanf("%d %d %d", &n, &m, &Q);
36         for (int i = 0; i < n; i++) {
37             scanf("%s", map[i]);
38         }
39         memset(mark, -1, sizeof(mark));
40         ans.clear();
41         _count = -1;
42         printf("Case %d:\n", t++);
43         while (Q--) {
44             int x, y;
45             scanf("%d %d", &x, &y);
46             x--, y--;
47             if (map[x][y] == '#') {
48                 puts("0");
49             }
50             else if (mark[x][y] == -1) {
51                 _count++;
52                 cnt = 0;
53                 dfs(x, y);
54                 ans.push_back(cnt);
55                 printf("%d\n", cnt);
56             }
57             else {
58                 printf("%d\n", ans[mark[x][y]]);
59             }
60         }
61     }
62     return 0;
63 }
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posted @ 2014-01-20 10:54  ihge2k  阅读(187)  评论(0编辑  收藏  举报