hdoj 1180 搜索 + bfs + 优先队列

题目

#include<iostream>
#include<queue>
#define MAX 22
#include<string.h>
using namespace std;

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

int vis[MAX][MAX];
char c;
int dir[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
int n, m;
int sx, sy;
char map[MAX][MAX];
int check(int x, int y){
if(x>=0 && x<n && y>=0 && y<m && !vis[x][y] && map[x][y]!='*')
return 1;
return 0;
}
Node t1, t2, node;
int bfs(int x, int y){
priority_queue<Node> pq;
node.x = x; node.y = y; node.s = 0;
pq.push(node);
vis[node.x][node.y] = 1;//标记已经访问
while(!pq.empty()){
t1 = pq.top();
pq.pop();
if(map[t1.x][t1.y] == 'T')
return t1.s;
//if(map[t2.x][t2.y] == 'T') return t2.s;
for(int i = 0; i < 4; ++i){
int nx = t1.x + dir[i][0];
int ny = t1.y + dir[i][1];
if(!check(nx,ny)) continue;
t2.x = nx; t2.y = ny; t2.s = t1.s+1;
//下一位置是楼梯时候才考虑 否则正常走
//有楼梯时*********************************
if(map[nx][ny] == '|' || map[nx][ny] == '-'){
if(t2.s%2 == 0){ //这里为偶数步时候 其之前一步的楼梯应该反向
if(map[nx][ny] == '|')
c = '-';
else if(map[nx][ny] == '-')
c = '|';
}
else
c = map[nx][ny];
t2.x += dir[i][0];
t2.y += dir[i][1];
if(!check(t2.x,t2.y)) continue;
if(c == '|' && (dir[i][1] == 1 || dir[i][1] == -1) || c == '-'&& (dir[i][0] == 1 || dir[i][0] == -1)){
t2.s += 1;//c表示到达楼梯前一步时候楼梯所处的状态
} //如果人沿着x（上下）走 楼梯横着 等待
//人沿着y（左右）走 楼梯 竖着等待
}
//***********************************
vis[t2.x][t2.y] = 1;
pq.push(t2);
}
}//end OF while
return -1;
}

int main()
{
while(scanf("%d%d",&n,&m)!=EOF){
for(int i = 0; i < n; ++i){
for(int j = 0; j < m; ++j){
cin >> map[i][j];
if(map[i][j] == 'S'){
sx = i; sy = j;
}
}
}
memset(vis,0,sizeof(vis));
int ans = bfs(sx, sy);
printf("%d\n",ans);
}

return 0;
}