hdu 5024 最长的L型

http://acm.hdu.edu.cn/showproblem.php?pid=5024

找到一个最长的L型，L可以是斜着的

简单的模拟

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <cstring>

#include <string>

#include <queue>

#include <vector>

#include <iostream>

#include <algorithm>

using namespace std;

#define RD(x) scanf("%d",&x)

#define RD2(x,y) scanf("%d%d",&x,&y)

#define clr0(x) memset(x,0,sizeof(x))

int n;

char s[115][115];

bool vis[115][115];

int dx[] = {1,-1,0,0,1,-1,1,-1},

    dy[] = {0,0,1,-1,-1,-1,1,1};

bool in(int x,int y)

{

    return 0 <= x && x < n && 0 <= y && y < n;

}

int find(int x,int y)

{

    int ans = 0;

    for(int i = 0;i < 8;++i)

    for(int j = i+1;j < 8;++j)if(dx[i]*dx[j] + dy[i]*dy[j] == 0){

        int xx = x + dx[i],yy = y + dy[i];

        int x1 = x + dx[j],y1 = y + dy[j];

        int res = 1;

        while(in(xx,yy) && s[xx][yy] == '.'){

            res++;

            xx += dx[i];

            yy += dy[i];

        }

        while(in(x1,y1) && s[x1][y1] == '.'){

            res++;

            x1 += dx[j];

            y1 += dy[j];

        }

        ans = max(res,ans);

    }

    return ans;

}

int main(){

    while(~RD(n) && n){

        //clr0(vis);

        for(int i = 0;i < n;++i){

            scanf("%s",s[i]);

        }

        int mx = 0;

        for(int i = 0;i < n;++i)

        for(int j = 0;j < n;++j){

            if(s[i][j] == '.'){

                mx = max(mx,find(i,j));

            }

        }

        printf("%d\n",mx);

     }

     return 0;

 }