Go: package main

import (
	"container/heap"
	"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 (pq PQStatus) Len() int {
	return len(pq)
}
func (pq PQStatus) Less(i, j int) bool {
	if pq[i].Turn == pq[j].Turn {
		return pq[i].Person.Distance() < pq[j].Person.Distance()
	}
	return pq[i].Turn < pq[j].Turn
}

func (pq PQStatus) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PQStatus) Push(x interface{}) {
	item := x.(*Status)
	*pq = append(*pq, item)
}

func (pq *PQStatus) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	*pq = old[0 : n-1]
	return item
}

func solve(h, w int64) {
	var tx, ty, kx, ky int64
	fmt.Scan(&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)
	heap.Init(&pq)
	heap.Push(&pq, start)
	dx := []int64{0, 1, 0, -1}
	dy := []int64{1, 0, -1, 0}
	memo := make(map[PersonPosition]struct{}, 0)
	for pq.Len() > 0 {
		now := heap.Pop(&pq).(*Status)
		if now.Person.Distance() == 0 {
			fmt.Println(now.Turn)
			return
		}
		if _, ok := memo[now.Person]; ok {
			continue
		}
		memo[now.Person] = struct{}{}
		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 += 1
			if next.Turn < 100 {
				heap.Push(&pq, next)
			}
		}
	}
	fmt.Println("NA")
}

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

C++: #include<bits/stdc++.h>
#define p pair<int,int>
#define P pair<p,p>
using namespace std;

int a[50][50][50][50];
int x[4] = { -1,0,0,1 }, y[4] = { 0,-1,1,0 };
int S[50][50];
signed main() {
	int b, c;
	while (cin >> c >> b, b | c) {
		memset(a, 0x3f, sizeof(a));
		int d, e, f, g; cin >> e >> d >> g >> f; d--; e--; f--; g--;
		a[d][e][f][g] = 0;
		for (int i = 0; i < b; i++) {
			for (int j = 0; j < c; j++) {
				scanf("%d", &S[i][j]);
			}
		}
		queue<P>Q;
		Q.push(P(p(d,e),p(f,g)));
		while (Q.size()) {
			P t = Q.front(); Q.pop();
			if (a[t.first.first][t.first.second][t.second.first][t.second.second] >= 100)break;
			if (t.first.first == t.second.first&&t.first.second == t.second.second) {
				cout << a[t.first.first][t.first.second][t.second.first][t.second.second] << endl;
				goto l;
		}
			for (int i = 0; i < 4; i++) {
				int j = 3 - i;
				p n, m; n = t.first; m = t.second;
				n.first += x[i]; n.second += y[i];
				m.first += x[j]; m.second += y[j];
				if (n.first < 0 || n.first >= b || n.second < 0 || n.second >= c||S[n.first][n.second]==1) {
					n.first -= x[i]; n.second -= y[i];
				}
				if (m.first < 0 || m.first >= b || m.second < 0 || m.second >= c||S[m.first][m.second]==1) {
					m.first -= x[j]; m.second -= y[j];
				}
				if (a[n.first][n.second][m.first][m.second] == 1061109567) {
					a[n.first][n.second][m.first][m.second] = a[t.first.first][t.first.second][t.second.first][t.second.second]+1;
					Q.push(P(p(n.first,n.second),p(m.first,m.second)));
				}
			}
		}
		puts("NA");
	l:;
	}
}

C++: #include<iostream>
#include<utility>
#include<queue>
#include<map>
using namespace std;
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };
int main() {
	int W, H, tx, ty, kx, ky;
	bool d[52][52];
	map<pair<pair<int, int>, pair<int, int> >,bool> m;
	pair<pair<int, int>, pair<int, int> >num;
	pair<pair<int, int>, pair<int, int> >copy;
	while (true) {
		cin >> W >> H;
		if (W == 0)break;
		for (int i = 0; i < H+2; i++) {
			for (int j = 0; j < W+2; j++) {
				d[i][j] = 1;
			}
		}
		cin >> tx >> ty >> kx >> ky;
		for (int i = 1; i < H + 1; i++) {
			for (int j = 1; j < W + 1; j++) {
				cin >> d[j][i];
			}
		}
		num.first.first = tx;
		num.first.second = ty;
		num.second.first = kx;
		num.second.second = ky;
		queue<pair<pair<int, int>, pair<int, int> > > q;
		bool flg = true;
		q.push(num);
		int qsize = q.size();
		int loopcount = 0;
		while (!q.empty()) {
			num = q.front();
			q.pop();
			if (qsize == 0) {
				qsize = q.size()+1;
				loopcount++;
				if (loopcount >= 100) {
					cout << "NA" << endl;
					flg = false;
					break;
				}
			}
			qsize--;
			if (num.first.first == num.second.first && num.first.second == num.second.second) {
				cout << ++loopcount << endl;
				flg = false;
				break;
			}
			for (int i = 0; i < 4; i++) {
				copy.first.first = num.first.first+dx[i];
				copy.first.second = num.first.second+dy[i];
				if (d[copy.first.first][copy.first.second]) {
					copy.first.first -= dx[i];
					copy.first.second -= dy[i];
				}
				copy.second.first =num.second.first-dx[i];
				copy.second.second =num.second.second- dy[i];
				if (d[copy.second.first][copy.second.second]) {
					copy.second.first += dx[i];
					copy.second.second += dy[i];
				}
				if (!m[copy]) {
					m[copy] = true;
					q.push(copy);
				}
			}
		}
		if (flg) {
			cout << "NA" << endl;
		}
	}
	return 0;
}