[HDOJ3580]Isosceles Right Triangles

暴力枚举即可（也可用dp实现）~

#include <cstdio>
#include <cstring>

 using namespace std;

 const int SIZE = 64;
const int TYPE = 26;

const int dx[] = {-1,0,1,0};
const int dy[] = {0,1,0,-1};
const int mx[] = {1,1,-1,-1};
const int my[] = {1,-1,-1,1};

const int ddx[] = {-1,1,1,-1};
const int ddy[] = {1,1,-1,-1};
const int mmx[] = {1,0,-1,0};
const int mmy[] = {0,-1,0,1};

char board[SIZE][SIZE];

bool visited[TYPE];
int count[TYPE];

int nn;

inline bool legal(int x,int y)
{
    return x >= 0 && x < nn && y >= 0 && y < nn;
}

void work(int x,int y,char ch)
{
    visited[ch-'A'] = true;
    for (int i = 0;i < 4;i++)
    {
        int j = (i + 1) % 4;
        for (int k = 1;;k++)
        {
            int sx = x + k * dx[i];
            int sy = y + k * dy[i];

            int ex = x + k * dx[j];
            int ey = y + k * dy[j];

            if (!legal(sx,sy) || !legal(ex,ey)) break;
            if (board[sx][sy] != ch || board[ex][ey] != ch) break;
            while (sx != ex || sy != ey)
            {
                sx += mx[i];
                sy += my[i];
                if (!legal(sx,sy) || board[sx][sy] != ch) break;
            }
            if (sx == ex && sy == ey) count[ch-'A']++;
            else break;
        }
    }

    for (int i = 0;i < 4;i++)
    {
        int j = (i + 1) % 4;
        for (int k = 1;;k++)
        {
            int sx = x + k * ddx[i];
            int sy = y + k * ddy[i];

            int ex = x + k * ddx[j];
            int ey = y + k * ddy[j];

            if (!legal(sx,sy) || !legal(ex,ey)) break;
            if (board[sx][sy] != ch || board[ex][ey] != ch) break;

            while (sx != ex || sy != ey)
            {
                sx += mmx[i];
                sy += mmy[i];
                if (!legal(sx,sy) || board[sx][sy] != ch) break;
            }
            if (sx == ex && sy == ey) count[ch-'A']++;
            else break;
        }
    }
}

int main()
{
    int cas;

    scanf("%d",&cas);

    for (int cc = 1;cc <= cas;cc++)
    {
        memset(count,0,sizeof(count));
        memset(visited,false,sizeof(visited));

        scanf("%d",&nn);
        for (int i = 0;i < nn;i++)
            scanf("%s",board[i]);

        for (int i = 0;i < nn;i++)
            for (int j = 0;j < nn;j++)
                work(i,j,board[i][j]);

        printf("Case %d:\n",cc);
        for (int i = 0;i < TYPE;i++)
            if (visited[i])
                printf("%c %d\n",'A' + i,count[i]);
    }
    return 0;
}