HDU1026 BFS&&优先队列&&路径保存

刚开始做BFS专题时遇到它，因为路径保存放弃了

现在做，刚开始各种WA。。。。。

后来加了个优先队列，就AC了。。额。。

#include<cstdio>#include<stdlib.h>#include<string.h>#include<string>#include<map>#include<cmath>#include<iostream>#include <queue>#include <stack>#include<algorithm>#include<set>using namespace std;#define inf 2147483647#define eps 1e-8#define LL long long#define M 50005#define mol 1000000007int mov[4][2]={{-1,0},{1,0},{0,-1},{0,1}};struct node{   int x,y,step;   friend bool operator<(node a,node b)   {       return a.step>b.step;   };};int n,m,vis[105][105];char s[105][105];int pd(int x,int y){   if(x>=0&&x<n&&y>=0&&y<m&&s[x][y]!='X')   return 1;   return 0;}struct dire{   int x,y;   }f[101][101];//保存当前点的前一点的位置void bfs(){   priority_queue<node>Q;   int ans=0,k,dx,dy;   f[n-1][m-1].x=-1;//终点标志   vis[n-1][m-1]=1;   node p,q;   p.x=n-1;   p.y =m-1;   p.step =0;   if(s[n-1][m-1]!='.')   p.step =s[n-1][m-1]-'0';   Q.push(p);   while(!Q.empty())   {       p=Q.top ();   Q.pop();   if(p.x==0&&p.y==0)   {   printf("It takes %d seconds to reach the target position, let me show you the way.\n",p.step);           k=1;   int a=p.x;//当前点   int b=p.y;   while(f[a][b].x!=-1)   {      int c=f[a][b].x;//当前点的前一点  int d=f[a][b].y;  printf("%ds:(%d,%d)->(%d,%d)\n",k++,a,b,c,d);  if(s[c][d]!='.')  {     for(int l=0;l<s[c][d]-'0';l++) printf("%ds:FIGHT AT (%d,%d)\n",k++,c,d);  }  a=c;  b=d;   }   printf("FINISH\n");   return;   }   q=p;   for(int i=0;i<4;i++)   {      dx =q.x +mov[i][0];  dy =q.y+mov[i][1];  if(vis[dx][dy]==0&&pd(dx,dy))  {      vis[dx][dy]=1;  p.x=dx;p.y=dy;    if(s[dx ][dy]!='.')  p.step =q.step +s[dx][dy]-'0'+1;  else  p.step =q.step +1;f[dx][dy].x=q.x;//路径保存f[dx][dy].y=q.y;  Q.push(p);  }   }   }   printf("God please help our poor hero.\nFINISH\n");   }int main(){while(~scanf("%d%d",&n,&m)){   int i,j;   memset(vis,0,sizeof(vis));   memset(f,0,sizeof(f));   for(i=0;i<n;i++)   {       scanf("%s",s[i]);   }   bfs();}return 0;}