hdoj 5335 Walk Out

 1     #include<stdio.h>
 2     #include<cstring>
 3     #include<cmath>
 4     #include<algorithm>
 5     using namespace std;
 6     const int MAXN = 1010;
 7     char R[MAXN][MAXN];
 8     bool used[MAXN][MAXN];
 9     int xx[1100000], yy[1100000];
10     int my[4] = { 0,  0,  1, -1};
11     int mx[4] = { 1, -1,  0,  0};
12     int n,m;
13     void bfs(){
14         memset(used,false,sizeof(used));
15         used[1][1] = true;
16         int p = 1, h = 1;
17         xx[p] = 1;
18         yy[p] = 1;
19         for(; p <= h; ++p)
20             if(R[xx[p]][yy[p]] == ‘0‘){
21                 for( int i = 0; i < 4; ++i){
22                     int X = xx[p]+mx[i];
23                     int Y = yy[p]+my[i];
24                     if( 0 < X && X <= n && 0 < Y && Y <= m && !used[X][Y]){
25                         h++;
26                         xx[h] = X;
27                         yy[h] = Y;
28                         used[X][Y] = true;
29                     }
30                 }
31         }//注意区分XY
32         if( R[n][m] == ‘0‘ && used[n][m]){
33             printf("0\n");
34             return;
35         }
36         int ma = 0;
37         for( int i = 1; i <= n; ++i)
38             for ( int j = 1; j <= m; ++j)
39                 if(used[i][j]){
40                     ma = max(ma,i+j);
41                 }
42         printf("1");
43         for( int i = ma; i < n+m; ++i){
44             char mi = ‘1‘;
45             for( int j = 1; j <= n; ++j )
46                 if( 1 <= i-j && i-j <= m && used[j][i-j]){
47                     mi = min(mi,R[j+1][i-j]);
48                     mi = min(mi,R[j][i-j+1]);
49                 }
50             printf("%c",mi);
51             for(int j = 1; j <= n; ++j )
52                 if( 1 <= i-j && i-j <= m && used[j][i-j]){
53                     if(R[j+1][i-j] == mi)
54                         used[j+1][i-j] = true;
55                     if(R[j][i-j+1] == mi)
56                         used[j][i-j+1] = true;
57                 }
58         }
59         printf("\n");
60     }
61     int main()
62     {
63         freopen("../Ъ§Он/1009/1009.in", "r", stdin);
64         freopen("a.out", "w", stdout);
65         int T;
66         scanf("%d",&T);
67         while(T--){
68             scanf("%d%d",&n,&m);
69             for( int i = 1; i <= n; ++i )
70                 scanf("%s",R[i]+1);
71             for (int i = 0; i <= n+1; ++i){
72                 R[i][0] = R[i][m+1] = ‘2‘;
73             }
74             for ( int i = 0; i <= m+1; ++i){
75                 R[0][i] = R[n+1][i] = ‘2‘;
76             }
77             bfs();
78 //            for ( int i = 0; i <= n +1; i++){
79 //                for( int j = 0; j <= m+1; j++)
80 //                    printf("%c",R[i][j]);
81 //                printf("\n");
82 //            }
83         }
84         return 0;
85     }