坑点极多的一道bfs好题！
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
using namespace std;
//Mystery_Sky
//
#define INF 0x3f3f3f3f
const int M = 100;
struct node{
int x, y, step, dirt, turn;//dirt取值为1， 2， 3， 4时别表示东，西，南，北。
node (int xx, int yy, int ss, int dd, int tt) : x(xx), y(yy), step(ss), dirt(dd), turn(tt){}
};
queue <node> q;
int n, m, ans, x1, x2, y1, y2;
char to;
int dis[M][M], map[M][M];
bool vis[M][M];
inline void bfs(int x1, int y1, int x2, int y2, char to)
{
int drt;
if(to == 'E') drt = 1;
else if(to == 'W') drt = 2;
else if(to == 'S') drt = 3;
else drt = 4;
q.push(node(x1, y1, 0, drt, 0));
while(!q.empty()) {
node top = q.front();
q.pop();
int dx, dy;
for(int i = 1; i <= 5; i++) {//i=4表示左转， i=5表示右转
if(i != 4 && i != 5) {
drt = top.dirt;
if(drt == 1) {
dx = top.x;
dy = top.y + i;
}
else if(drt == 2) {
dx = top.x;
dy = top.y - i;
}
else if(drt == 3) {
dx = top.x + i;
dy = top.y;
}
else {
dx = top.x - i;
dy = top.y;
}
if(map[dx][dy] == 1) i = 3;
if(dx <= 0 || dy <= 0 || dx > n || dy > n) {
i = 3;
continue;
}
if(vis[dx][dy]) {
continue;
}
if(dx == x2 && dy == y2) {
dis[x2][y2] = top.step + 1;
return;
}
dis[dx][dy] = min(top.step + 1, dis[dx][dy]);
vis[dx][dy] = 1;
q.push(node(dx, dy, top.step+1, drt, 0));
}
else if(i == 4){
int t = top.turn;
if(t > 2) continue;
dx = top.x, dy = top.y;
drt = top.dirt;
if(drt == 1) drt = 4;
else if(drt == 2) drt = 3;
else if(drt == 3) drt = 1;
else drt = 2;
dis[dx][dy] = min(top.step + 1, dis[dx][dy]);
vis[dx][dy] = 1;
q.push(node(dx, dy, top.step + 1, drt, t+1));
}
else {
int t = top.turn;
if(t > 2) continue;
dx = top.x, dy = top.y;
drt = top.dirt;
if(drt == 1) drt = 3;
else if(drt == 2) drt = 4;
else if(drt == 3) drt = 2;
else drt = 1;
dis[dx][dy] = min(top.step + 1, dis[dx][dy]);
vis[dx][dy] = 1;
q.push(node(dx, dy, top.step + 1, drt, t+1));
}
}
}
return;
}
int main() {
int a;
scanf("%d%d", &n, &m);
for(int i = 1; i <= n; i++)
for(int j = 1; j <= m; j++) {
scanf("%d", &a);
if(a == 1) {
vis[i][j] = vis[i][j+1] = vis[i+1][j] = vis[i+1][j+1] = 1;
map[i][j] = map[i][j+1] = map[i+1][j] = map[i+1][j+1] = 1;
}
}
n++, m++;
for(int i = 1; i <= m; i++) vis[1][i] = vis[n][i] = 1;
for(int i = 1; i <= n; i++) vis[i][1] = vis[i][m] = 1;
scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
getchar();
x1++, x2++, y1++, y2++;
scanf("%c", &to);
memset(dis, INF, sizeof(dis));
if(vis[x1][y1] || vis[x2][y2]) return 0 * printf("-1
");
if(x1 == x2 && y1 == y2) return 0 * printf("0
");
bfs(x1, y1, x2, y2, to);
// for(int i = 1; i <= n; i++){
// for(int j = 1; j <= m; j++){
// if(dis[i][j] == INF) printf("-1 ");
// else printf("%d ", dis[i][j]);
// }
// printf("
");
// }
if(dis[x2][y2] == INF) printf("-1
");
else printf("%d
", dis[x2][y2]);
return 0;
}