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\n",ans);

114     }

115     return 0;

116 }