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 {
				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 <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.first == ck.first && ct.second == ck.second) return visited[picked];
		for(int i = 0;i < 4;++i){
			pair<P, P> nextp;
			P nextt, nextk;
			int tdx, tdy, kdx, kdy;
			tdx = dx[i]; tdy = dy[i];
			kdx = tdx * -1; kdy = tdy * -1;
			nextt = board[ct.first + tdx][ct.second + tdy] != guard ? make_pair(ct.first + tdx, ct.second + tdy) : ct;
			nextk = board[ck.first + kdx][ck.second + kdy] != guard ? make_pair(ck.first + kdx, ck.second + kdy) : ck;
			nextp = make_pair(nextt, nextk);
			if(visited[nextp] == 0 || visited[nextp] > visited[picked] + 1){
				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), -1);
		}
		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 != guard) cout << res << endl;
		else cout << "NA" << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int table[51][51];

bool memo[51][51][51][51];

int main() {

    while(1){

        int w,h;

        //scanf(" %d %d",&w,&h);

        cin >> w >> h;

        if(w==0&&h==0) break;

        int tx,ty,kx,ky;

        //scanf(" %d %d %d %d",&tx,&ty,&kx,&ky);

        cin >> tx >> ty >> kx >> ky;

        tx--;ty--;kx--;ky--;

        for(int i=0;i<51;i++){
            for(int j=0;j<51;j++){
                table[i][j] = 1;
                for(int k=0;k<51;k++){
                    for(int r=0;r<51;r++){
                        memo[i][j][k][r] = false;
                    }
                }
            }
        }

        for(int i=0;i<w;i++){
            for(int j=0;j<h;j++){
                //scanf(" %d",&table[i][j]);
                cin >> table[i][j];
                if(table[i][j] == 1){
                    for(int k=0;k<51;k++){
                        for(int r=0;r<51;r++){
                            memo[i][j][k][r] = true;
                        }
                    }
                }
            }
        }

        /*printf("\n");

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                printf("%d ",table[i][j]);
            }
            printf("\n");
        }*/

        //memset(memo,false,sizeof(memo));

        queue<vector<int> > q;

        vector<int> v(5);

        v[0] = tx; v[1] = ty; v[2] = kx; v[3] = ky; v[4] = 0;

        if(table[v[0]][v[1]] == 1 || table[v[2]][v[3]] == 1){
            cout << "NA" << endl;
            continue;
        }

        q.push(v);

        bool check = false;

        while(!q.empty()){

            v = q.front(); q.pop();

            if(memo[v[0]][v[1]][v[2]][v[3]]){
                continue;
            }

            if(v[0] == v[2] && v[1] == v[3]){
                check = true;
                cout << v[4] << endl;
                break;
            }

            memo[v[0]][v[1]][v[2]][v[3]] = true;

            v[4]++;

            if(v[4] >= 100){
                break;
            }

            vector<int> before(5);

            for(int i=0;i<5;i++){
                before[i] = v[i];
            }

            v[0]--; v[2]++;

            if(v[0] == -1 || table[v[0]][v[1]] == 1){
                v[0]++;
            }
            if(v[2] == w || table[v[2]][v[3]] == 1){
                v[2]--;
            }

            q.push(v);

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[0]++; v[2]--;

            if(v[2] == -1 || table[v[2]][v[3]] == 1){
                v[2]++;
            }
            if(v[0] == w || table[v[0]][v[1]] == 1){
                v[0]--;
            }

            q.push(v);


            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[1]++; v[3]--;

            if(v[3] == -1 || table[v[2]][v[3]] == 1){
                v[3]++;
            }
            if(v[1] == h || table[v[0]][v[1]] == 1){
                v[1]--;
            }

            q.push(v);

            for(int i=0;i<5;i++){
                v[i] = before[i];
            }

            v[1]--; v[3]++;

            if(v[1] == -1 || table[v[0]][v[1]] == 1){
                v[1]++;
            }
            if(v[3] == h || table[v[2]][v[3]] == 1){
                v[3]--;
            }

             q.push(v);
        }

        if(!check){
            cout << "NA" << endl;
        }



    }

    return 0;
}