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)
	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 < 100-1 {
				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<stdio.h>
#include<iostream>
#include<queue>
using namespace std;
struct oza{
	int x;
	int y;
};
int A[52][52][52][52];
int main(){
	oza k;
	oza t;
	queue<oza> ka;
	queue<oza> ta;
	queue<int> Z;
	int  w,h,b;
	int d=0,c=0,i=0,j=0,l=-1,D[52][52];
	int tx[4]={ 1, 0,-1,0 };       
	int kx[4]={-1, 0, 1,0 };
	int ty[4]={ 0, 1, 0,-1 };
	int ky[4]={ 0, -1, 0,1};
	scanf("%d %d",&w,&h);
	while(w!=0&&h!=0){
	memset(A,0,sizeof(A));
		for(i=0;i<=h+1;i++){
		for(j=0;j<=w+1;j++){
		D[i][j]=1; //??¨????????????????????\?????? 
		}
	}

	scanf("%d %d",&t.x,&t.y);
	scanf("%d %d",&k.x,&k.y);
	for(i=1;i<=h;i++){
		for(j=1;j<=w;j++){
		scanf("%d",&D[i][j]);
		}
	}
	ta.push(t);
	ka.push(k);
	Z.push(c);
		if(t.x==k.x&&t.y==k.y){
			d=-1;
		}
	while(d!=-1){
		l++;
		if(l==4){
		l=0;
		t=ta.front();
		k=ka.front();
		ka.pop();
		ta.pop();
		Z.pop();
		A[t.x][t.y][k.x][k.y]=1;
		}
		if(c==100||Z.empty()){
			printf("NA");
		break;
		}
	
		// ?????\????????????????????¨?????¨??????
		t=ta.front();
		k=ka.front();
		c=Z.front();
		
		t.x=t.x+tx[l];
		t.y=t.y+ty[l];
		k.x=k.x+kx[l];
		k.y=k.y+ky[l];
		
		if(D[t.x][t.y]==1){
		t.x=t.x-tx[l];
		t.y=t.y-ty[l];
		}
		if(D[k.x][k.y]==1){
		k.x=k.x-kx[l];
		k.y=k.y-ky[l];
		}
		if(A[t.x][t.y][k.x][k.y]==1){
			continue;
		}
		
		ta.push(t);
		ka.push(k);
		c=c+1;
		Z.push(c);
		
		if(t.x==k.x&&t.y==k.y){
			printf("%d\n",Z.back());
			break;
		}	
		
		
	}
	while(!ka.empty()){
	ka.pop();
	ta.pop();
	Z.pop();
	}
	c=0;
	l=-1;
	scanf("%d %d",&w,&h);
	}	
	return 0;

}

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

int dx[4] = { -1,0,0,1 }, dy[4] = { 0,-1,1,0 };
int main() {
	int a, b;
	while (cin >> b>>a, a | b) {
		int c, d, e, f;
		cin >> c >> d >> e >> f;
		c--; d--; e--; f--;
		bool ba[50][50];
		int k[50][50];
		memset(k, -1, sizeof(k));
		for (int g = 0; g < a; g++) {
			for (int h = 0; h < b; h++) {
				cin >> ba[g][h];
			}
		}
		if ((((c - e) & 1) == 0) && (((d - f) & 1) == 0)) {
			queue<P>Q;
			if (!ba[c][d] && !ba[e][f]) {
				Q.push(P(c, d));
				k[c][d] = 0;
			}
			while (Q.size()) {
				P o = Q.front(); Q.pop();
				for (int i = 0; i < 4; i++) {
					int x = dx[i],y=dy[i];
						if (o.first + x >= 0 && o.first + x < a&&o.second + y >= 0 && o.second + y < b) {
							if (c + e - (o.first + x) >= 0 && c + e - (o.first + x) < a&&d + f - (o.second + y) >= 0 && d + f - (o.second + y) < b) {
								if (!ba[o.first + x][o.second + y] && !ba[c + e - (o.first + x)][d + f - (o.second + y)] && k[o.first + x][o.second + y] == -1) {
									Q.push(P(o.first + x, o.second + y));
									k[o.first + x][o.second + y] = k[o.first][o.second] + 1;
								}
							}
						}
				}
			}
			for (int n = 0; n < a; n++) {
				for (int m = 0; m < b; m++) {
					cout << k[n][m]<<" ";
				}
				cout << endl;
			}
		}
		else puts("NA");
	}
}

C++: #include <bits/stdc++.h>

using namespace std;

class Position {
public:
	int tx, ty, kx, ky;
	int cnt;

	Position() {
		tx = ty = kx = ky = cnt = 0;
	}

	Position(int x1, int y1, int x2, int y2) : tx(x1), ty(y1), kx(x2), ky(y2) {
		cnt = 0;
	}
};

int W, H, Ans;
int MapData[50][50];
int Dx[4] = { 1,0,-1,0 };
int Dy[4] = { 0,1,0,-1 };
bool Visited[50][50][50][50];

bool solve(int x1, int y1, int x2, int y2) {
	int curTx, curTy, curKx, curKy, nextTx, nextTy, nextKx, nextKy;
	queue<Position> positionList;
	Position curPos, next;

	memset(Visited, false, sizeof(Visited));
	positionList.push(Position(x1, y1, x2, y2));
	while (!positionList.empty()) {
		curPos = positionList.front();
		positionList.pop();

		if (curPos.cnt == 100) {
			return false;
		}
		curTx = curPos.tx;
		curTy = curPos.ty;
		curKx = curPos.kx;
		curKy = curPos.ky;
		if (curTx == curKx && curTy == curKy) {
			Ans = curPos.cnt;
			return true;
		}
		if (Visited[curTx][curTy][curKx][curKy]) {
			continue;
		}
		Visited[curTx][curTy][curKx][curKy] = true;
		next.cnt = curPos.cnt + 1;

		for (int i = 0; i < 4; ++i) {
			nextTx = curTx + Dx[i];
			nextTy = curTy + Dy[i];
			nextKx = curKx - Dx[i];
			nextKy = curKy - Dy[i];
			if (nextTx < 0 || nextTx > W - 1 || nextTy < 0 || nextTy > H - 1 || MapData[nextTy][nextTx] == 1) {
				next.tx = curTx;
				next.ty = curTy;
			}
			else {
				next.tx = nextTx;
				next.ty = nextTy;
			}

			if (nextKx < 0 || nextKx > W - 1 || nextKy < 0 || nextKy > H - 1 || MapData[nextKy][nextKx] == 1) {
				next.kx = curKx;
				next.ky = curKy;
			}
			else {
				next.kx = nextKx;
				next.ky = nextKy;
			}
			positionList.push(next);
		}
	}

	return false;
}

int main() {
	int x1, y1, x2, y2;

	while (cin >> W >> H, W) {
		cin >> x1 >> y1 >> x2 >> y2;
		for (int i = 0; i < H; ++i) {
			for (int j = 0; j < W; ++j) {
				cin >> MapData[i][j];
			}
		}
		if (solve(--x1, --y1, --x2, --y2)) {
			cout << Ans << endl;
		}
		else {
			cout << "NA" << endl;
		}
	}

	return 0;
}