[BFS] HDU 2102

#include <cstdio>
#include <cstring>
#include <iostream>
#include <queue>

using namespace std;

struct Node {
int x, y, z;
int cnt;
};

int n, m, t;
//两层
char maze[ 2 ][ 35 ][ 35 ];
bool vis[ 2 ][ 35 ][ 35 ];
int dir[ 4 ][ 2 ] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};

bool path ( int x, int y, int z ) {
if ( x < 0 || x >= n || y < 0 || y >= m || maze[ z ][ x ][ y ] == '*' )
return false;

//进不了的入口直接屏蔽掉
if ( maze[ z ][ x ][ y ] == '#' &&
( maze[ !z ][ x ][ y ] == '#' || maze[ !z ][ x ][ y ] == '*' ) )
return false;

return true;
}

bool bfs () {
Node cur, nex;

cur.x = cur.y = cur.z = 0;
cur.cnt = 0;
vis[ cur.z ][ cur.x ][ cur.y ] = true;

queue<Node> Q;
Q.push ( cur );

while ( !Q.empty () ) {
cur = Q.front ();
Q.pop ();

//超过时限
if ( cur.cnt > t )
return false;

//找到结果
if ( maze[ cur.z ][ cur.x ][ cur.y ] == 'P' ) {
return true;
}

for ( int i = 0; i < 4; ++i ) {
nex.x = cur.x + dir[ i ][ 0 ];
nex.y = cur.y + dir[ i ][ 1 ];
nex.z = cur.z;

if ( path ( nex.x, nex.y, nex.z ) && !vis[ nex.z ][ nex.x ][ nex.y ] ) {
if ( maze[ nex.z ][ nex.x ][ nex.y ] ==
'#' ) //找到传送站直接换到另一层，不算时间
nex.z = !cur.z;
nex.cnt = cur.cnt + 1;
vis[ nex.z ][ nex.x ][ nex.y ] = true;

Q.push ( nex );
}
}
}

return false;
}

int main () {
int c;
scanf ( "%d", &c );
while ( c-- ) {
scanf ( "%d%d%d", &n, &m, &t );

memset ( vis, false, sizeof ( vis ) );

for ( int i = 0; i < n; ++i )
scanf ( "%s", maze[ 0 ][ i ] );
for ( int i = 0; i < n; ++i )
scanf ( "%s", maze[ 1 ][ i ] );

bool flag = bfs ();

if ( flag )
printf ( "YES\n" );
else
printf ( "NO\n" );
}
}