2802:小游戏利用bfs来实现

#include <bits/stdc++.h>
using namespace std;
class Node{
        //int direct,step;
    public:
        int x,y;
        Node(int x_,int y_):x(x_),y(y_){}
};
class directNode{
    public:
        int direct,step;
        directNode(int direct_,int step_):direct(direct_),step(step_){}
};
int w,h;
char s[100][100];
int  mark[100][100];
directNode * directStep[100][100];
int direction[4][2]={{-1,0},{0,1},{1,0},{0,-1}};
int totalStep=100000;
queue<Node *> ques;
void findTotalPath(int x1,int y1,int x2,int y2,int direct,int step){
    while(ques.size()>0){
        Node * temp=ques.front();
        //cout<<temp->x<<"-"<<temp->y<<endl;
        if(temp->x==x2&&temp->y==y2){
            if(totalStep>directStep[temp->y][temp->x]->step&&directStep[temp->y][temp->x]->step!=0){
                totalStep=directStep[temp->y][temp->x]->step;
                continue;
            }
        }
        for(int i=0;i<4;i++){
            int xx1=temp->x+direction[i][1];
            int yy1=temp->y+direction[i][0];
            if((xx1>-1)&&(xx1<w+2)&&(yy1>-1)&&(yy1<h+2)&&(s[yy1][xx1]==‘ ‘||(yy1==y2&&xx1==x2&&s[yy1][xx1]==‘X‘))){
                //cout<<"* "<<directStep[temp->y][temp->x]->step<<","<<directStep[temp->y][temp->x]->direct<<endl;
                int tempStep=directStep[temp->y][temp->x]->direct!=i?directStep[temp->y][temp->x]->step+1:directStep[temp->y][temp->x]->step;
                if(mark[yy1][xx1]==1){
                    if(directStep[yy1][xx1]->step>tempStep){
                        directStep[yy1][xx1]->direct=i;
                        directStep[yy1][xx1]->step=tempStep;
                    }
                }else{
                    ques.push(new Node(xx1,yy1));
                    directStep[yy1][xx1]->direct=i;
                    directStep[yy1][xx1]->step=tempStep;
                    mark[yy1][xx1]=1;
                    //cout<<xx1<<" "<<yy1<<endl;
                    //cout<<"tempStep:"<<tempStep<<endl;
                }
            }
        }
        ques.pop();
    }
}
int main(){
    int id=1;
    while(1){
        /*cin>>w>>h;
        cin.ignore();*/
        scanf("%d %d",&w,&h);
        if(w==0&&h==0) break;
        /*for(int i=0;i<h+2;i++){
            s[i][0]=s[i][w+1]=‘ ‘;
        }
        for(int j=0;j<w+2;j++){
            s[0][j]=s[w+1][j]=‘ ‘;
        }*/
        for(int i=0;i<h+2;i++){
            for(int j=0;j<w+2;j++){
                directStep[i][j]=new directNode(-1,0);
            }
        }
        for (int i = 0; i <100; i ++) s[0][i] =s[i][0] = ‘ ‘;
        for(int i=1;i<h+1;i++){
            getchar();
            //string str="";
            //getline(cin,str);
            for(int j=1;j<w+1;j++){
                //s[i][j]=str[j-1];
                s[i][j]=getchar();
            }
        }
        for (int i = 0; i <= w; i ++)
            s[h + 1][i + 1] = ‘ ‘;
        for (int i = 0; i <= h; i ++)
            s[i + 1][w + 1] = ‘ ‘;
        cout<<"Board #"<<id<<":"<<endl;
        id++;
        int x1,y1,x2,y2;
        int subId=0;
        while(1){
            subId++;
             totalStep=100000;
             memset(mark, 100000, sizeof(mark));
            cin>>x1>>y1>>x2>>y2;
            ques.push(new Node(x1,y1));
            mark[y1][x1]=1;
            if(x1==0&&y1==0&&x2==0&&y2==0) break;
            int step=0;
            int direct=-1;
            findTotalPath(x1,y1,x2,y2,direct,step);
            if(totalStep<100000)
                cout<<"Pair "<<subId<<": "<<totalStep<<" segments."<<endl;
            else{
                cout<<"Pair "<<subId<<": "<<"impossible."<<endl;
            }
            for(int i=0;i<h+2;i++){
                for(int j=0;j<w+2;j++){
                    directStep[i][j]=new directNode(-1,0);
                }
        }
        }
        while(ques.size()>0){
            ques.pop();
        }
        cout<<endl;
    }
}