poj3669 Meteor Shower(BFS)

题目链接:poj3669 Meteor Shower

我只想说这题WA了后去看讨论才发现的坑点，除了要注意原点外，流星范围题目给的是[0,300]，到302的位置就绝对安全了。。。

 #include<cstdio>
 #include<cmath>
 #include<queue>
 #include<cstring>
 #include<algorithm>
 #define CLR(a,b) memset((a),(b),sizeof((a)))
 using namespace std;

 const int N = ;
 const int inf = 0x3f3f3f3f;
 int dir[][]={-,,,,,,,-};
 int vis[N][N], g[N][N];
 struct point{
     int x, y;
     int d;
     point(int x=,int y=,int d=):x(x),y(y),d(d){}
 };
 int jud(int x, int y, int d){
     if(x >= && x < N && y >=  && y < N && !vis[x][y] && d < g[x][y])
         return ;
     return ;
 }
 int bfs(){
     CLR(vis, );
     queue<point>q;
     point u, v;
     vis[][] = ;
     q.push(point(,,));
     while(!q.empty()){
         u = q.front(); q.pop();
         for(int i = ; i < ; ++i){
             v.x = u.x + dir[i][];
             v.y = u.y + dir[i][];
             v.d = u.d + ;
             if(jud(v.x, v.y, v.d)){
                 if(g[v.x][v.y] == inf)//安全区域
                     return v.d;
                 vis[v.x][v.y] = ;
                 q.push(v);
             }
         }
     }
     return -;
 }
 int main(){
     int m, i, x, y, t;
     CLR(g,inf);
     scanf("%d", &m);
     for(i = ; i < m; ++i){
         scanf("%d%d%d", &x, &y, &t);
         g[x][y] = min(t, g[x][y]);
         if(x >  && t < g[x-][y])
             g[x-][y] = t;
         if(y >  && t < g[x][y-])
             g[x][y-] = t;
         g[x+][y] = min(t, g[x+][y]);
         g[x][y+] = min(t, g[x][y+]);
     }
     if(g[][] == ){printf("-1\n");return ;}
     if(g[][] == inf){printf("0\n");return ;}
     printf("%d\n",bfs());
     return ;
 }