poj 2935 bfs

来源：互联网发布：软件行业就业前景编辑：程序博客网时间：2024/06/08 08:52
#include<iostream>#include<cstdio>#include<algorithm>#include<cstring>#include<queue>#include<stack>using namespace std;const int maxn=15;int dir[maxn][maxn],map[maxn][maxn][4],sx,sy,ex,ey;int help[4][2]={1,0,0,1,-1,0,0,-1};char s[4]={'S','E','N','W'};typedef struct {int x,y;}node;void init(){    memset(map,0,sizeof(map));    memset(dir,-1,sizeof(dir));}void solve(){    queue<node> que;    node tp={sx,sy};dir[sx][sy]=0;    que.push(tp);    while(que.size())    {        node tmp=que.front();        que.pop();        for(int i=0;i<4;i++)        {            node tpp={tmp.x+help[i][0],tmp.y+help[i][1]};            if(tpp.x>=1&&tpp.x<=6&&tpp.y>=1&&tpp.y<=6&&dir[tpp.x][tpp.y]==-1&&!map[tmp.x][tmp.y][i])            {                que.push(tpp);                dir[tpp.x][tpp.y]=i;                if(tpp.x==ex&&tpp.y==ey)        return;            }        }    }}void prinf(){    stack<int> stc;    node now={ex,ey};    while(!(now.x==sx&&now.y==sy))    {        int tp=dir[now.x][now.y];stc.push(tp);        tp=(tp+2)%4;        now.x+=help[tp][0];        now.y+=help[tp][1];    }    while(stc.size())    {        printf("%c",s[stc.top()]);        stc.pop();    }printf("\n");}int main(){    int tx1,ty1,tx2,ty2;    while(scanf("%d%d",&sy,&sx)!=EOF&&(sx||sy))    {        scanf("%d%d",&ey,&ex);        if(sx==ex&&sy==ey) {printf("\n");continue;}        init();        for(int i=1;i<=3;i++)        {            scanf("%d%d%d%d",&ty1,&tx1,&ty2,&tx2);            if(tx1==tx2)            {                if(ty1>ty2)                    swap(ty1,ty2);                while(ty1<ty2)                {map[tx1][ty1+1][0]=map[tx1+1][ty1+1][2]=1;                    ty1++;                }            }            else            {                if(tx1>tx2)                    swap(tx1,tx2);                while(tx1<tx2)                {                    map[tx1+1][ty1][1]=map[tx1+1][ty1+1][3]=1;                    tx1++;                }            }        }        solve();        prinf();    }    return 0;}
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