HDU-4618 Palindrome Sub-Array 暴力枚举

　　题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4618
　　直接暴力枚举中心点，在中间如果求不出最大值直接跳过优化下。。。
  1 //STATUS:C++_AC_31MS_800KB
  2 #include <functional>
  3 #include <algorithm>
  4 #include <iostream>
  5 //#include <ext/rope>
  6 #include <fstream>
  7 #include <sstream>
  8 #include <iomanip>
  9 #include <numeric>
 10 #include <cstring>
 11 #include <cassert>
 12 #include <cstdio>
 13 #include <string>
 14 #include <vector>
 15 #include <bitset>
 16 #include <queue>
 17 #include <stack>
 18 #include <cmath>
 19 #include <ctime>
 20 #include <list>
 21 #include <set>
 22 #include <map>
 23 #pragma comment(linker,"/STACK:102400000,102400000")
 24 using namespace std;
 25 //using namespace __gnu_cxx;
 26 //define
 27 #define pii pair<int,int>
 28 #define mem(a,b) memset(a,b,sizeof(a))
 29 #define lson l,mid,rt<<1
 30 #define rson mid+1,r,rt<<1|1
 31 #define PI acos(-1.0)
 32 //typedef
 33 typedef __int64 LL;
 34 typedef unsigned __int64 ULL;
 35 //const
 36 const int N=310,M=2000010;
 37 const int INF=0x3f3f3f3f;
 38 const int MOD=100000,STA=8000010;
 39 const LL LNF=1LL<<60;
 40 const double EPS=1e-8;
 41 const double OO=1e15;
 42 const int dx[4]={-1,0,1,0};
 43 const int dy[4]={0,1,0,-1};
 44 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
 45 //Daily Use ...
 46 inline int sign(double x){return (x>EPS)-(x<-EPS);}
 47 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
 48 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
 49 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
 50 template<class T> inline T Min(T a,T b){return a<b?a:b;}
 51 template<class T> inline T Max(T a,T b){return a>b?a:b;}
 52 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
 53 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
 54 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
 55 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
 56 //End
 57 
 58 int w[N][N];
 59 int T,n,m,ans;
 60 
 61 int slove(int x,int y)
 62 {
 63     int i,j,c,ok,ret=1;
 64     for(c=ok=1;x-c>=0&&x+c<n && y-c>=0&&y+c<m;c++){
 65         for(i=0;i<=c;i++){
 66             if(w[x-c+i][y-c]!=w[x-c+i][y+c]
 67                || w[x-c][y-c+i]!=w[x+c][y-c+i]
 68                || w[x+i][y-c]!=w[x-i][y-c]
 69                || w[x+i][y+c]!=w[x-i][y+c]
 70                || w[x-c][y-i]!=w[x-c][y+i]
 71                || w[x+c][y-i]!=w[x+c][y+i]){ok=0;break;}
 72         }
 73         if(!ok)break;
 74     }
 75     ret=(c-1)<<1|1;
 76     for(c=ok=1;x-c+1>=0&&x+c<n && y-c+1>=0&&y+c<m;c++){
 77         for(i=0;i<=c;i++){
 78             if(w[x-c+i+1][y-c+1]!=w[x-c+i+1][y+c]
 79                || w[x-c+1][y-c+i+1]!=w[x+c][y-c+i+1]
 80                || w[x+i][y-c+1]!=w[x-i+1][y-c+1]
 81                || w[x+i][y+c]!=w[x-i+1][y+c]
 82                || w[x-c+1][y-i+1]!=w[x-c+1][y+i]
 83                || w[x+c][y-i+1]!=w[x+c][y+i]){ok=0;break;}
 84         }
 85         if(!ok)break;
 86     }
 87     return Max(ret,(c-1)<<1);
 88 }
 89 
 90 int main()
 91 {
 92  //   freopen("in.txt","r",stdin);
 93     int i,j;
 94     scanf("%d",&T);
 95     while(T--)
 96     {
 97         scanf("%d%d",&n,&m);
 98         for(i=0;i<n;i++){
 99             for(j=0;j<m;j++){
100                 scanf("%d",&w[i][j]);
101             }
102         }
103 
104         ans=1;
105         for(i=0;i<n;i++){
106             if( ((i+1)<<1)<=ans || (((n-i-1)<<1)|1)<=ans)continue;
107             for(j=0;j<m;j++){
108                 if( ((j+1)<<1)<=ans || (((m-j-1)<<1)|1)<=ans)continue;
109                     ans=Max(ans,slove(i,j));
110             }
111         }
112 
113         printf("%d
",ans);
114     }
115     return 0;
116 }