HDU4528 + BFS

#include<stdio.h>#include<string.h>#include<stdlib.h>#include<algorithm>#include<iostream>#include<queue>#include<stack>#include<math.h>#include<map>using namespace std;const int maxn = 115;const int inf = 9999999;char mat[ maxn ][ maxn ];int vis[ maxn ][ maxn ][ 2 ][ 2 ];const int dx[]={1,-1,0,0};const int dy[]={0,0,1,-1};struct Pos{int x,y;};struct Node{int x,y,ti;int D,E;//flag};Pos D,S,E;void init(){for( int i=0;i<maxn;i++ )for( int j=0;j<maxn;j++ )mat[i][j] = 'X';}bool in( Node p,int n,int m ){if( p.x>=0&&p.x<n&&p.y>=0&&p.y<m )return true;elsereturn false;}bool Judge1( Node tmp ){int x = tmp.x;int y1 = min( tmp.y,D.y );int y2 = max( tmp.y,D.y );for( int i=y1+1;i<y2;i++ ){if( mat[x][i]=='X' ) return false;else if( mat[x][i]=='.' ){if( x==D.x&&i==D.y ) return false;else if( x==E.x&&i==E.y ) return false;}}return true;}bool Judge2( Node tmp ){int x = tmp.x;int y1 = min( tmp.y,E.y );int y2 = max( tmp.y,E.y );for( int i=y1+1;i<y2;i++ ){if( mat[x][i]=='X' ) return false;else if( mat[x][i]=='.' ){if( x==D.x&&i==D.y ) return false;else if( x==E.x&&i==E.y ) return false;}}return true;}bool Judge3( Node tmp ){int y = tmp.y;int x1 = min( tmp.x,D.x );int x2 = max( tmp.x,D.x );for( int i=x1+1;i<x2;i++ ){if( mat[i][y]=='X' ) return false;else if( mat[i][y]=='.' ){if( i==D.x&&y==D.y ) return false;else if( i==E.x&&y==E.y ) return false;}}return true;}bool Judge4( Node tmp ){int y = tmp.y;int x1 = min( tmp.x,E.x );int x2 = max( tmp.x,E.x );for( int i=x1+1;i<x2;i++ ){if( mat[i][y]=='X' ) return false;else if( mat[i][y]=='.' ){if( i==D.x&&y==D.y ) return false;else if( i==E.x&&y==E.y ) return false;}}return true;}int bfs( int n,int m,int aim_ti ){Node cur,nxt;cur.x = S.x;cur.y = S.y;cur.ti = 0;cur.D = cur.E = 0;queue<Node>q;while( !q.empty() )q.pop();q.push( cur );int ans = inf;vis[ cur.x ][ cur.y ][ cur.D ][ cur.E ] = 1;while( !q.empty() ){cur = q.front();q.pop();if( cur.ti>aim_ti ) continue;//printf("cur:x=%d,y=%d,ti=%d\n",cur.x,cur.y,cur.ti);if( cur.x==D.x&&Judge1( cur )==true ) cur.D = 1;if( cur.x==E.x&&Judge2( cur )==true ) cur.E = 1;if( cur.y==D.y&&Judge3( cur )==true ) cur.D = 1;if( cur.y==E.y&&Judge4( cur )==true ) cur.E = 1;if( cur.D==1 ) {if( cur.E==1 ){if( ans>cur.ti ){ans = cur.ti;}}}//printf("ans:%d\n",ans);for( int i=0;i<4;i++ ){nxt = cur;nxt.x+=dx[i];nxt.y+=dy[i];nxt.ti++;if( in( nxt,n,m )==true&&mat[nxt.x][nxt.y]!='X'&&vis[nxt.x][nxt.y][nxt.D][nxt.E]==0 ){vis[nxt.x][nxt.y][nxt.D][nxt.E] = 1;q.push(nxt);}}}if( ans>aim_ti ) return -1;else return ans;}int main(){int ca,T;scanf("%d",&ca);T = 1;while( ca-- ){int n,m,aim_ti;printf("Case %d:\n",T++);init();scanf("%d%d%d",&n,&m,&aim_ti);for( int i=0;i<n;i++ ){scanf("%s",mat[i]);for( int j=0;j<m;j++ ){if( mat[i][j]=='D' ){D.x = i;D.y = j;mat[i][j]='X';}else if( mat[i][j]=='S' ){S.x = i;S.y = j;mat[i][j]='.';}else if( mat[i][j]=='E' ){E.x = i;E.y = j;mat[i][j]='X';}}}memset( vis,0,sizeof( vis ) );int ans = bfs( n,m,aim_ti );printf("%d\n",ans);}return 0;}