Go: package main

import (
	"fmt"
	"math"
)

type Position struct {
	X int64
	Y int64
}

func (one Position) Distance(another Position) int64 {
	return int64(math.Abs(float64(one.X-another.X)) + math.Abs(float64(one.Y-another.Y)))
}

type PersonPosition struct {
	Takayuki Position
	Kazuyuki Position
}

func (one PersonPosition) Distance() int64 {
	return one.Takayuki.Distance(one.Kazuyuki)
}

type Status struct {
	Person PersonPosition
	Turn   int64
}

type PQStatus []*Status

func solve(h, w int64) {
	var tx, ty, kx, ky int64
	fmt.Scan(&tx, &ty, &kx, &ky)
	tx--
	ty--
	kx--
	ky--
	m := make([][]int64, h)
	for i := range m {
		m[i] = make([]int64, w)
		for j := int64(0); j < w; j++ {
			fmt.Scan(&m[i][j])
		}
	}
	start := &Status{Person: PersonPosition{Takayuki: Position{X: tx, Y: ty}, Kazuyuki: Position{X: kx, Y: ky}}, Turn: 0}
	pq := make(PQStatus, 0)
	pq = append(pq, start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]int64, 0)
	ans := int64(102)
	for len(pq) > 0 {
		now := &Status{}
		*now = *pq[0]
		pq = pq[1:]
		if now.Person.Distance() == 0 && ans > now.Turn {
			ans = now.Turn
		}
		if ans <= now.Turn {
			continue
		}

		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = now.Turn

		for i := 0; i < 4; i++ {
			next := &Status{}
			*next = *now
			next.Person.Kazuyuki.X += dx[i]
			next.Person.Kazuyuki.Y += dy[i]
			if next.Person.Kazuyuki.X < 0 || next.Person.Kazuyuki.X >= w ||
				next.Person.Kazuyuki.Y < 0 || next.Person.Kazuyuki.Y >= h ||
				m[next.Person.Kazuyuki.Y][next.Person.Kazuyuki.X] == 1 {
				next.Person.Kazuyuki.X -= dx[i]
				next.Person.Kazuyuki.Y -= dy[i]
			}
			next.Person.Takayuki.X -= dx[i]
			next.Person.Takayuki.Y -= dy[i]
			if next.Person.Takayuki.X < 0 || next.Person.Takayuki.X >= w ||
				next.Person.Takayuki.Y < 0 || next.Person.Takayuki.Y >= h ||
				m[next.Person.Takayuki.Y][next.Person.Takayuki.X] == 1 {
				next.Person.Takayuki.X += dx[i]
				next.Person.Takayuki.Y += dy[i]
			}
			next.Turn++
			if next.Turn <= 100 {
				pq = append(pq, next)
			}
		}
	}
	if ans == 102 {
		fmt.Println("NA")
	} else {
		fmt.Println(ans)
	}
}

func main() {
	var h, w int64
	for {
		fmt.Scan(&h, &w)
		if h == 0 && w == 0 {
			break
		}
		solve(h, w)
	}
}

C++: #include<queue>
#include<vector> 
#include<iostream>
#include<algorithm>
using namespace std;
int same[55][55][55][55] = { 0 };
struct maigo{
	int x[2];// ????????????[0]???????????????[1]
	int y[2];// ????????????[0]???????????????[1]
	int count;
};
int main(){
	queue<maigo> q;
	int tx, ty; int kx, ky;
	int **depart, X, Y;
	int flag = 0, a = 0;
	int c = 0;
	int f = 0;
	cin >> X >> Y;
	while (X != 0 && Y != 0){
		depart = new int*[Y + 2];
		for (int i = 0; i < Y + 2; i++){
			depart[i] = new int[X + 2];
		}
		for (int i = 0; i < Y + 2; i++){
			for (int l = 0; l < X + 2; l++){
				depart[i][l] = 3;
			}
		}
		cin >> tx >> ty;
		cin >> kx >> ky;
		for (int i = 1; i < Y + 1; i++){
			for (int l = 1; l < X + 1; l++){
				cin >> depart[i][l];
			}
		}
		maigo temp;
		temp.x[0] = tx; temp.y[0] = ty;
		temp.x[1] = kx; temp.y[1] = ky;
		temp.count = 1;
		q.push(temp);
		while (!q.empty()&&flag == 0){
			maigo t = q.front();
			maigo into;
			q.pop();
			same[t.x[0]][t.y[0]][t.x[1]][t.y[1]] = 1;
			if (t.count >= 100){
				a = 1; flag = 1;
				break;
			}
			int dx1[4] = { 1, 0, -1, 0 }; int dx2[4] = { 0, 1, 0, -1 };
			for (int i = 0; i < 4; i++){
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] == 0 &&
					depart[t.x[1] - dx1[i]][t.y[1] - dx2[i]] == 0 &&
					same[t.x[0] + dx1[i]][t.y[0] + dx2[i]][t.x[1] - dx1[i]][t.y[1] - dx2[i]]){
					if (t.x[0] + dx1[i] == t.x[1] + dx1[i] * (-1) &&
						t.y[0] + dx2[i] == t.y[1] + dx2[i] * (-1)){
						cout << t.count << endl;
						flag = 1;
					}
					into.x[0] = t.x[0] + dx1[i], into.y[0] = t.y[0] + dx2[i];
					into.x[1] = t.x[1] + dx1[i] * (-1), into.y[1] = t.y[1] + dx2[i] * (-1);

					into.count = t.count + 1;
					q.push(into);
				}
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] == 0 && //???????????? ok ???????????? no ?????´???
					depart[t.x[1] - dx1[i]][t.y[1] - dx2[i]] != 0 &&
					same[t.x[0] + dx1[i]][t.y[0] + dx2[i]][t.x[1]][t.y[1]]){
					if (t.x[0] + dx1[i] == t.x[1] &&
						t.y[0] + dx2[i] == t.y[1]){
						cout << t.count << endl;
						flag = 1;
					}
					into.x[0] = t.x[0] + dx1[i], into.y[0] = t.y[0] + dx2[i];
					into.x[1] = t.x[1], into.y[1] = t.y[1];

					into.count = t.count + 1;
					q.push(into);
				}
				if (depart[t.x[0] + dx1[i]][t.y[0] + dx2[i]] != 0 && //???????????? no??????????????? yes????????´???
					depart[t.x[1] - dx1[i]][t.y[1] - dx2[i]] == 0 &&
					same[t.x[0]][t.y[0]][t.x[1] - dx1[i]][t.y[1] - dx2[i]]){
					if (t.x[0] == t.x[1] + dx1[i] * (-1) &&
						t.y[0] == t.y[1] + dx2[i] * (-1)){
						cout << t.count << endl;
						flag = 1;
					}
					into.x[0] = t.x[0], into.y[0] = t.y[0];
					into.x[1] = t.x[1] + dx1[i] * (-1), into.y[1] = t.y[1] + dx2[i] * (-1);

					into.count = t.count + 1;
					q.push(into);
				}
			}
		}if (a == 1 || flag == 0) {
			cout << "NA" << endl;
		}while (!q.empty()) q.pop();
		a = 0; flag = 0;
		cin >> X >> Y;
	}
	return 0;
}

C++: #include <iostream>
#include <queue>
#include <utility>
#include <set>
#include <vector>
using namespace std;

int main(void) {
	int X, Y;

	while(cin >> X >> Y, X | Y) {
		pair<int,int> t, k;
		vector<vector<int> > depart;
		set<pair<pair<int,int>,pair<int,int> > > moved;
		queue<pair<pair<pair<int,int>, pair<int,int> >, int> > q;
		int ans = -1;

		cin >> t.second >> t.first; t.first--; t.second--;
		cin >> k.second >> k.first; k.first--; k.second--;

		for(int i = 0; i < Y; i++) {
			vector<int> v;
			for(int j = 0; j < X; j++) {
				int tmp;
				cin >> tmp;
				v.push_back(tmp);
			}
			depart.push_back(v);
		}

		moved.insert(make_pair(t, k));
		q.push(make_pair(make_pair(t,k), 0));

		for(int i = 0;; i++) {
			pair<pair<int,int>, pair<int, int> > p;
			pair<int, int> next_t, next_k;
			int n;

			if(q.empty()) {
				break;
			}

			p = q.front().first; n = q.front().second; q.pop();
			if(p.first == p.second) {
				ans = n;
				break;
			}
			if(n > 100)
				break;

			int direction[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
			for(int j = 0; j < 4; j++) {
				next_t.first = p.first.first; next_t.second = p.first.second;
				next_k.first = p.second.first; next_k.second = p.second.second;
				if(0 <= p.first.first + direction[j][0] && p.first.first + direction[j][0] < Y 
						&& 0 <= p.first.second + direction[j][1] && p.first.second + direction[j][1] < X 
						&& depart[p.first.first + direction[j][0]][p.first.second + direction[j][1]] == 0) {
					next_t.first = p.first.first + direction[j][0];
					next_t.second = p.first.second + direction[j][1];
				}
				if(0 <= p.second.first - direction[j][0] && p.second.first - direction[j][0] < Y 
						&& 0 <= p.second.second - direction[j][1] && p.second.second - direction[j][1] < X 
						&& depart[p.second.first - direction[j][0]][p.second.second - direction[j][1]] == 0) {
					next_k.first = p.second.first - direction[j][0];
					next_k.second = p.second.second - direction[j][1];
				}
				if(moved.insert(make_pair(next_t, next_k)).second) {
					q.push(make_pair(make_pair(next_t, next_k),n + 1));
				}
			}
		}

		if(ans != -1)
			cout << ans << endl;
		else
			cout << "NA" << endl;
	}
}