解けないなあ……

0223.cpp

#include <iostream>
#include <algorithm>
#include <queue>
#include <utility>
#include <map>
using namespace std;

const int Y = 50, X = 50, GUARD = 1;
typedef pair<int, int> P;


int bfs(const int (*board)[Y + 2], P t, P k){
	int dx[] = {0, -1, 1, 0}, dy[] = {-1, 0, 0, 1};
	// pair<P, P> -> first = t, second = k
	queue<pair<P, P> > q;
	map<pair<P, P>, int> visited;
	q.push(make_pair(t, k));
	visited[make_pair(t, k)] = 0;
	while(!q.empty()){
		pair<P, P> picked = q.front();
		q.pop();
		if(visited[picked] >= 100) break;
		P ct = picked.first, ck = picked.second;
		if(ct == ck) return visited[picked];
		for(int i = 0;i < 4;++i){
			pair<P, P> nextp;
			P nextt, nextk;
			int tdx, tdy, kdx, kdy;
			int ntx, nty, nkx, nky;

			tdx = dx[i];
			tdy = dy[i];
			kdx = -tdx;
			kdy = -tdy;

			ntx = ct.first + tdx;
			nty = ct.second + tdy;
			nkx = ck.first + kdx;
			nky = ck.second + kdy;

			nextt = board[ntx][nty] != GUARD ? P(ntx, nty) : P(ct.first, ct.second);
			nextk = board[nkx][nky] != GUARD ? P(nkx, nky) : P(ck.first, ck.second);
			nextp = make_pair(nextt, nextk);

			if(visited[nextp] == 0){
				q.push(nextp);
				visited[nextp] = visited[picked] + 1;
			}
		}
	}
	return -1;
}

int main(){
	int board[X + 2][Y + 2];
	int x, y, a, res;
	P t, k;
	while(cin >> x >> y, x && y){
		for(int i = 0;i <= X + 1;++i){
			fill(board[i], board[i] + (Y + 2), GUARD);
		}
		cin >> t.first >> t.second;
		cin >> k.first >> k.second;
		for(int i = 1;i <= y;++i){
			for(int j = 1;j <= x;++j){
				cin >> a;
				board[i][j] = a;
			}
		}
		res = bfs(board, t, k);
		if(res != -1) cout << res << endl;
		else cout << "NA" << endl;
	}
	return 0;
}