思路 ： 直接枚举
1 /* 2 PROG: Finding crosses 3 ID : 4 LANG: C++ 5 */ 6 //#pragma warnning (diaable : 4530) 7 //#pragma warnning (disable : 4786) 8 9 #include <set> 10 #include <map> 11 #include <list> 12 #include <stack> 13 #include <queue> 14 #include <cmath> 15 #include <string> 16 #include <vector> 17 #include <utility> 18 #include <cmath> 19 #include <cstdio> 20 #include <cstdlib> 21 #include <cstring> 22 #include <iostream> 23 #include <fstream> 24 #include <algorithm> 25 26 using namespace std; 27 28 #define DEBUG 0 29 30 const int MAXN = 52; 31 const int dx[] = {-1, 0, 1, 0}; 32 const int dy[] = {0, 1, 0, -1}; 33 34 int N; 35 char graph[MAXN][MAXN]; 36 37 void readGraph() { 38 for (int ix = 0; ix < N; ++ix) 39 scanf("%s", graph[ix]); 40 } 41 42 bool isNotOkey(int x, int y) { 43 return (x < 0 || y < 0 || x >= N || y >= N || graph[x][y] != '#'); 44 } 45 46 int countGrids(int x, int y, int dir) { 47 int ax, ay, ret = 0; 48 49 while (!isNotOkey(x, y)) { 50 ax = x + dx[(dir + 1) % 4]; 51 ay = y + dy[(dir + 1) % 4]; 52 if (!isNotOkey(ax, ay)) return 0; 53 54 ax = x + dx[(dir + 3) % 4]; 55 ay = y + dy[(dir + 3) % 4]; 56 if (!isNotOkey(ax, ay)) return 0; 57 58 ++ret, x += dx[dir], y += dy[dir]; 59 }// End of while 60 return ret; 61 } 62 63 void Solve() { 64 int cross = 0, grids[4] = {0}; 65 66 for (int ix = 0; ix < N; ++ix) { 67 for (int jx = 0; jx < N; ++jx) { 68 if (graph[ix][jx] == '#') { 69 memset(grids, 0, sizeof(grids)); // record the grids 70 for (int kx = 0; kx < 4; ++kx) { 71 int nx = ix + dx[kx]; 72 int ny = jx + dy[kx]; 73 grids[kx] = countGrids(nx, ny, kx); 74 } 75 if (grids[0] && grids[0] == grids[1] 76 && grids[0] == grids[2] && grids[0] == grids[3]) { 77 ++cross; 78 } 79 }// End of if 80 } 81 }// End of for 82 printf("%d\n", cross); 83 } 84 85 int main() { 86 #if DEBUG 87 freopen("E:\\hdoj_4414.in", "r", stdin); 88 freopen("E:\\hdoj_4414.out", "w", stdout); 89 #endif 90 91 while (~scanf("%d", &N), N != 0) { 92 readGraph(); 93 Solve(); 94 }// End of while 95 return 0; 96 } 97 /* 98 7 99 ooo#ooo 100 ooo#ooo 101 o###### 102 ooo#ooo 103 ooo#ooo 104 ooo#ooo 105 ooooooo 106 0 107 108 Run ID Submit Time Judge Status Pro.ID Exe.Time Exe.Memory Code Len. Language Author 109 6847615 2012-10-01 15:29:57 Accepted 4414 0MS 232K 1833 B C++ Maxwell 110 */