BOJ 1461

bfs搜索

转动平面相当于改变重力的方向

#include <cstdio>#include <cstring>#include <queue>#define N 110using namespace std;struct line{int x0,y0,x1,y1;bool flag; //flag=1从左到右}lines[N];struct Point{int x,y,dir;};bool vis[N][N][4];bool isin[N][N][4];int dp[N][N][4]; //0表示重力向下 1表示重力向左...int x0,y0,x1,y1;int w,h,n;int dir[4][2]={0,-1,-1,0,0,1,1,0};//二位数组按行存储（WA死了）bool check(int x,int y){if(x>=0 && x<w && y>=0 && y<h)return 1;return 0;}int bfs(){                     //其实这里直接bfs搜即可，不用写成SPFAqueue<Point>q;Point p1,p2;int i,j;memset(dp,-1,sizeof(dp));memset(isin,0,sizeof(isin));dp[x0][y0][0]=0;isin[x0][y0][0]=0;p1.x=x0,p1.y=y0,p1.dir=0,q.push(p1);while(!q.empty()){p1=q.front();q.pop();if(p1.x==x1 && p1.y==y1) return dp[x1][y1][p1.dir];int nowdir=(p1.dir+1)%4,x=p1.x,y=p1.y;while(check(x+dir[nowdir][0],y+dir[nowdir][1]) && !(x==x1 && y==y1) && !vis[x][y][nowdir]) x+=dir[nowdir][0],y+=dir[nowdir][1];if(dp[x][y][nowdir]==-1){dp[x][y][nowdir]=dp[p1.x][p1.y][p1.dir]+1;if(isin[x][y][nowdir]==0){p2.x=x,p2.y=y,p2.dir=nowdir;isin[x][y][nowdir]=1;q.push(p2);}}nowdir=(p1.dir+3)%4,x=p1.x,y=p1.y;        while(check(x+dir[nowdir][0],y+dir[nowdir][1]) && !(x==x1 && y==y1) && !vis[x][y][nowdir]) x+=dir[nowdir][0],y+=dir[nowdir][1];if(dp[x][y][nowdir]==-1){dp[x][y][nowdir]=dp[p1.x][p1.y][p1.dir]+1;if(isin[x][y][nowdir]==0){p2.x=x,p2.y=y,p2.dir=nowdir;isin[x][y][nowdir]=1;q.push(p2);}        }isin[p1.x][p1.y][p1.dir]=0;}return -1;}int main(){int t,T;int i,j;scanf("%d",&T);for(t=1;t<=T;t++){scanf("%d %d %d",&w,&h,&n);scanf("%d %d %d %d",&x0,&y0,&x1,&y1);memset(vis,0,sizeof(vis));for(i=1;i<=n;i++){scanf("%d %d %d %d",&lines[i].x0,&lines[i].y0,&lines[i].x1,&lines[i].y1);if(lines[i].x0==lines[i].x1){     // ==老写错for(j=lines[i].y0;j<lines[i].y1;j++) vis[lines[i].x0-1][j][3]=1,vis[lines[i].x0][j][1]=1;}else{for(j=lines[i].x0;j<lines[i].x1;j++) vis[j][lines[i].y0-1][2]=1,vis[j][lines[i].y0][0]=1;}}//for(j=0;j<w;j++) vis[0][j][0]=1,vis[h-1][j][2]=1;//for(j=0;j<h;j++) vis[j][0][1]=1,vis[j][w-1][3]=1;printf("%d\n",bfs());  } }