hdoj 1254 推箱子 bfs嵌套

这题一边听着歌，一边做，结果相当悲剧。WA了无数次。。。。

看来BFS写得还是要规范点，这样细节上才能减少出错。

#include <iostream>
#include <cmath>
#include <queue>
using namespace std;

struct Position {
	int x, y;
};

struct Status {
	Position person, box;
	int deep;
}_s;

int mp[10][10], n, m;
int dir[4][2] = { 1, 0, 0, -1, -1, 0, 0, 1 };
Status person, box;
Position end;


void input() {
	int i, j;
	scanf( "%d %d", &n, &m );
	for( i=0; i<n; ++i ) {
		for( j=0; j<m; ++j ) {
			scanf( "%d", &mp[i][j] );
			if( mp[i][j] == 2 ) {
				_s.box.x = i;
				_s.box.y = j;
			} else if( mp[i][j] == 4 ) {
				_s.person.x = i;
				_s.person.y = j;
			}
		}
	}
}



inline bool isBond( Position p ) {
	if( p.x < 0 || p.y < 0 || p.x >= n || p.y >= m || mp[p.x][p.y] == 1) return 1;
	return 0;
}

bool canPush(Position pp, Status s) {
	queue<Position> Q;
	bool mark[10][10];
	Position p, q;
	int i;

	memset( mark, 0, sizeof(mark));
	Q.push( pp );
	mark[pp.x][pp.y] = 1;
	mark[s.box.x][s.box.y] = 1;
	while( !Q.empty() ) {
		p = Q.front();
		Q.pop();
		if( p.x == s.person.x && p.y == s.person.y ) return 1;
		for( i=0; i<4; ++i ) {
			q = p;
			q.x += dir[i][0];
			q.y += dir[i][1];
			if( isBond(q) || mark[q.x][q.y] ) continue;
			mark[q.x][q.y] = 1;
			Q.push( q );
		}
	}
	return 0;
}



int canReach() {
	queue<Status> Q;
	bool mark[10][10][4];
	Status p, q;
	Position pp;
	int i;

	memset( mark, 0, sizeof(mark));
	_s.deep = 0;
	Q.push( _s );
	while( !Q.empty() ) {
		p = Q.front();
		Q.pop();
		if( mp[p.box.x][p.box.y] == 3 ) return p.deep;
		for( i=0; i<4; ++i ) {
			q.box.x = p.box.x + dir[i][0];
			q.box.y = p.box.y + dir[i][1];
			q.deep = p.deep + 1;
			if( isBond(q.box) || mark[q.box.x][q.box.y][i] ) continue;
			pp.x = p.box.x - dir[i][0];
			pp.y = p.box.y - dir[i][1];
			if( isBond( pp ) || !canPush(pp, p) ) continue; 
			q.person = p.box;
			mark[q.box.x][q.box.y][i] = 1;
			Q.push( q );
		}
	}
	return -1;
}




int main() {
//	freopen( "c:/aaa.txt", "r", stdin );
	int T;
	scanf( "%d", &T );
	while( T-- ) {
		input();
		printf( "%d\n", canReach() );
	}
	return 0;
}

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