hdu1180 诡异的楼梯--BFS

原题链接：​​http://acm.hdu.edu.cn/showproblem.php?pid=1180​​

需要注意这句话：Harry每秒只能停留在'.'或'S'和'T'所标记的格子内.

#define _CRT_SECURE_NO_DEPRECATE 
#define _CRT_SECURE_Cy1_OVERLOAD_STANDARD_NAMES 1 

#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <queue>
#include <string.h>
using namespace std;

const int N = 50;
const int INF = 1000000;

char Map[N][N];
bool vis[N][N];
int n, m;

int dir[4][2] = { { 1, 0 },{ -1, 0 },{ 0, 1 },{ 0, -1 } };

struct node
{
  int x, y;
  int step;
  friend bool operator < (const node &a, const node &b)
  {
    return a.step > b.step;
  }
};

node st;

bool check(int x, int y)
{
  if (x >= 0 && x < n && y >= 0 && y < m && !vis[x][y] && Map[x][y] != '*') 
    return true;
  else 
    return false;
}

int bfs(int x, int y)
{
  char c;
  priority_queue <node> q;
  node s_pos;
  s_pos.x = x;
  s_pos.y = y;
  s_pos.step = 0;
  vis[s_pos.x][s_pos.y] = 1;
  q.push(s_pos);
  while (!q.empty())
  {
    node tmp = q.top();
    q.pop();
    for (int i = 0; i < 4; i++)
    {
      node tmp2;
      tmp2 = tmp;
      tmp2.x += dir[i][0];
      tmp2.y += dir[i][1];
      tmp2.step += 1;
      if (check(tmp2.x, tmp2.y) && (Map[tmp2.x][tmp2.y] == '-' || Map[tmp2.x][tmp2.y] == '|'))
      {
        if (tmp2.step % 2 == 1)
        {
          if (Map[tmp2.x][tmp2.y] == '-') c = '|';
          else if (Map[tmp2.x][tmp2.y] == '|') c = '-';
        }
        else c = Map[tmp2.x][tmp2.y];

        tmp2.x += dir[i][0];//????
        tmp2.y += dir[i][1];

        if ((c == '-' && (dir[i][1] == -1 || dir[i][1] == 1)) || (c == '|' && (dir[i][0] == -1 || dir[i][0] == 1)))
          tmp2.step += 1;
        
      }
      if (check(tmp2.x, tmp2.y))
      {
        if (Map[tmp2.x][tmp2.y] == 'T') return tmp2.step;
        vis[tmp2.x][tmp2.y] = 1;
        q.push(tmp2);
      }
    }
  }
  return -1;
}

int main()
{
  while (~scanf("%d%d", &n, &m))
  {
    for (int i = 0; i < n; i++)
      for (int j = 0; j < m; j++)
      {
        cin >> Map[i][j];
        if (Map[i][j] == 'S')
        {
          st.x = i;
          st.y = j;
        }
      }
    memset(vis, 0, sizeof(vis));
    int ans = bfs(st.x, st.y);
    printf("%d\n", ans);
  }
  return 0;
}