题目链接：https://www.luogu.org/problemnew/show/P1825
带有传送门的迷宫问题
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 2001;
char map[maxn][maxn];
int fx[4] = {0, 1, 0, -1};
int fy[4] = {1, 0, -1, 0};
int n, m, ex, ey, sx, sy;
struct map{
int x, y, t;
}q[4000001];
struct door{
int x1, y1, x2, y2;
}d[40];
void bfs()
{
int head = 1, tail = 2;
q[head].x = sx, q[head].y = sy, q[head].t = 0;
while(head != tail)
{
for(int i = 0; i < 4; i++)
{
int nowx = q[head].x + fx[i];
int nowy = q[head].y + fy[i];
if(nowx == ex && nowy == ey)
{
printf("%d", q[head].t + 1);
return ;
}
if(nowx > n || nowx <= 0 || nowy > m || nowy <= 0 || map[nowx][nowy] == '#') continue;
if(map[nowx][nowy] >= 'A' && map[nowx][nowy] <= 'Z')
{
if(nowx == d[map[nowx][nowy]-'A'].x1 && nowy == d[map[nowx][nowy]-'A'].y1)
{
q[tail].x = d[map[nowx][nowy]-'A'].x2;
q[tail].y = d[map[nowx][nowy]-'A'].y2;
q[tail].t = q[head].t + 1;
tail++;
}
if(nowx == d[map[nowx][nowy]-'A'].x2 && nowy == d[map[nowx][nowy]-'A'].y2)
{
q[tail].x = d[map[nowx][nowy]-'A'].x1;
q[tail].y = d[map[nowx][nowy]-'A'].y1;
q[tail].t = q[head].t + 1;
tail++;
}
}
else
{
map[nowx][nowy] = '#';
q[tail].x = nowx;
q[tail].y = nowy;
q[tail].t = q[head].t + 1;
tail++;
}
}
head++;
}
}
int main()
{
cin>>n>>m;
for(int i = 1; i <= n; i++)
for(int j = 1; j <= m; j++)
{
cin>>map[i][j];
if(map[i][j] == '@') sx = i, sy = j;
if(map[i][j] == '=') ex = i, ey = j;
if(map[i][j] <= 'Z' && map[i][j] >= 'A')
{
if(d[map[i][j]-'A'].x1 == 0 && d[map[i][j]-'A'].y1 == 0)
{d[map[i][j]-'A'].x1 = i, d[map[i][j]-'A'].y1 = j; continue;}
if(d[map[i][j]-'A'].x2 == 0 && d[map[i][j]-'A'].y2 == 0)
{d[map[i][j]-'A'].x2 = i, d[map[i][j]-'A'].y2 = j; continue;}
}
}
bfs();
return 0;
}