HDOJ - 4414 (Finding crosses)

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 */