hdu5024-Wang Xifeng's Little Plot

此题一开始用暴力做，后来发现斜着走的时候其实暴力不太好写，于是改用搜索写了

 

  1 #include <iostream>
  2 #include <stdio.h>
  3 #include <memory.h>
  4 using namespace std;
  5 
  6 char a[110][110]= {0};
  7 int down[110][110]= {0};
  8 int up[110][110]= {0};
  9 
 10 int cnt[110][110][4]= {0};
 11 int n;
 12 int dx[4]= {-1,1,-1, 1};
 13 int dy[4]= {-1,1, 1,-1};
 14 int dfs(int curx,int cury,int num)
 15 {
 16     if(curx<0 || cury<0 || curx>=n || cury>=n)
 17         return 0;
 18     int &ans=cnt[curx][cury][num];
 19     if(a[curx][cury]=='#')
 20         return ans=0;
 21     return ans=1+dfs(curx+dx[num],cury+dy[num],num);
 22 }
 23 
 24 
 25 int getMax()
 26 {
 27     int ans=0;
 28     for(int i=0; i<n; i++)
 29         for(int j=0; j<n; j++)
 30         {
 31             ans=max(ans,down[i][j]+up[i][j]-1);
 32         }
 33     return ans;
 34 }
 35 
 36 int main()
 37 {
 38     freopen("in.txt","r",stdin);
 39 
 40     while(scanf("%d",&n),n)
 41     {
 42         memset(down,0,sizeof down);
 43         memset(up,0,sizeof up);
 44         memset(cnt,0,sizeof cnt);
 45         for(int i=0; i<n; i++)
 46             scanf("%s",a[i]);
 47 
 48         for(int i=0; i<n; i++)
 49             for(int j=0; j<n; j++)
 50             {
 51                 if(a[i][j]=='#')
 52                 {
 53                     up[i][j]=down[i][j]=0;
 54 
 55                 }
 56                 else
 57                 {
 58                     up[i][j]=down[i][j]=1;
 59                     if(i!=0)
 60                         up[i][j]=up[i-1][j]+1;
 61                     if(j!=0)
 62                         down[i][j]=down[i][j-1]+1;
 63                 }
 64             }
 65 
 66         int ans=0;
 67         ans=max(ans,getMax());
 68 
 69         memset(down,0,sizeof down);
 70         memset(up,0,sizeof up);
 71         for(int i=n-1; i>=0; i--)
 72             for(int j=n-1; j>=0; j--)
 73             {
 74                 if(a[i][j]=='#')
 75                 {
 76                     up[i][j]=down[i][j]=0;
 77                 }
 78                 else
 79                 {
 80                     up[i][j]=down[i][j]=1;
 81                     if(i!=n-1)
 82                         up[i][j]=up[i+1][j]+1;
 83                     if(j!=n-1)
 84                         down[i][j]=down[i][j+1]+1;
 85                 }
 86             }
 87 
 88         ans=max(ans,getMax());
 89 
 90 //---------------------------
 91         memset(down,0,sizeof down);
 92         memset(up,0,sizeof up);
 93         for(int i=0; i<n; i++)
 94             for(int j=n-1; j>=0; j--)
 95             {
 96                 if(a[i][j]=='#')
 97                 {
 98                     up[i][j]=down[i][j]=0;
 99                 }
100                 else
101                 {
102                     up[i][j]=down[i][j]=1;
103                     if(i!=0)
104                         up[i][j]=up[i-1][j]+1;
105                     if(j!=n-1)
106                         down[i][j]=down[i][j+1]+1;
107                 }
108             }
109 
110         ans=max(ans,getMax());
111 //-------------------------------
112         memset(down,0,sizeof down);
113         memset(up,0,sizeof up);
114         for(int i=n-1; i>=0; i--)
115             for(int j=0; j<n; j++)
116             {
117                 if(a[i][j]=='#')
118                 {
119                     up[i][j]=down[i][j]=0;
120                 }
121                 else
122                 {
123                     up[i][j]=down[i][j]=1;
124                     if(i!=n-1)
125                         up[i][j]=up[i+1][j]+1;
126                     if(j!=0)
127                         down[i][j]=down[i][j-1]+1;
128                 }
129             }
130 
131         ans=max(ans,getMax());
132 //--------------------------------------------------
133 
134         for(int i=0; i<n; i++)
135             for(int j=0; j<n; j++)
136             {
137                 for(int num=0; num<4; num++)
138                 {
139                     dfs(i,j,num);
140                 }
141             }
142 
143         for(int i=0; i<n; i++)
144             for(int j=0; j<n; j++)
145             {
146                 ans=max(ans,cnt[i][j][0]+cnt[i][j][2]-1);
147                 ans=max(ans,cnt[i][j][0]+cnt[i][j][3]-1);
148                 ans=max(ans,cnt[i][j][1]+cnt[i][j][3]-1);
149                 ans=max(ans,cnt[i][j][1]+cnt[i][j][2]-1);
150             }
151 
152         cout<<ans<<endl;
153     }
154     return 0;
155 }

 

posted @ 2014-09-20 17:38  PlasticSpirit  阅读(304)  评论(0)  编辑  收藏  举报