hdu1728 广搜

提示：每个点可以多次搜索，但是要判断是否是较优解，用visit数组保存每个点的最优解，即最少转弯次数。

#include<iostream>
#include<cstdio>
#include<queue>
#include<memory.h>
using namespace std;
 struct node{
    int x,y,direction;
    int turn;
    };
    int tnum,si,sr,ei,er,h,l;
    char map[101][101];
    int visit[101][101];
    #define reset(f,n) memset(f,0,sizeof(f));
    int dire[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
    void bfs()
    {
        int i,r,t;
        queue<node> qlist;
        node head;
        head.x=si-1;
        head.y=sr-1;
        head.direction=-1;
        head.turn=0;
        visit[si-1][sr-1]=0;
        qlist.push(head);
        while(!qlist.empty())
        {
            node nownode=qlist.front();
            qlist.pop();
            int k=4;
            while(k--)
            {
                i=nownode.x+dire[k][0];
                r=nownode.y+dire[k][1];
               //   cout<<i<<" "<<r<<endl;
                if(map[i][r]=='.'&&i<h&&i>=0&&r<l&&r>=0)
                {
                    if(nownode.direction!=-1&&nownode.direction!=k)
                    {
                        t=nownode.turn+1;
                    }
                    else
                    t=nownode.turn;
                    if(t>tnum)continue;          
                    if(i==ei-1&&r==er-1)
                       {
                        //cout<<temp.x<<" "<<temp.y<<" "<<temp.turn<<" "<<temp.direction<<" ";
                        cout<<"yes"<<endl;
                        return;
                        }
                    if(visit[i][r]>=t){
                    node temp;
                    temp.x=i;
                    temp.y=r;
                    temp.direction=k;
                    temp.turn=t;
                    qlist.push(temp);
                    visit[i][r]=t;
                      //cout<<i<<" "<<r<<endl;
                }    
                }
            }
        }
        cout<<"no"<<endl;
        return;
    }    
    int main()
    {
        int n;
        int i,r;
        cin>>n;
        while(n--)
        {
            reset(visit,0);
            cin>>i>>r;
            h=i;
            l=r;
            for(int i1=0;i1<i;i1++)
            for(int r1=0;r1<r;r1++)
            {
                cin>>map[i1][r1];
                visit[i1][r1]=50;
            }
            cin>>tnum>>sr>>si>>er>>ei;
            bfs();
        }   
        return 0;
    }