Go: // BFS

package main

import (
	"bufio"
	"os"
		"fmt"
	"strconv"
	"strings"
)

var scanner = bufio.NewScanner(os.Stdin)

var p = [15]int{}
var g = [13][4]int {
	// -1は存在しないマス目
	{2,-1,-1,-1},
	{2,5,-1,-1},{0,1,3,6},{2,7,-1,-1},
	{5,-1,-1,-1},{1,4,6,9},{2,5,7,10},{3,6,8,11},{7,-1,-1,-1},
	{5,10,-1,-1},{6,9,11,12},{7,10,-1,-1},
	{10,-1,-1,-1},
}

/*
　  ０ １ ２ ３ ４
 0 |／|／|  |／|／|
 1 |／|　|  |　|／|
 2 |　|　|  |　|　|
 3 |／|　|  |　|／|
 4 |／|／|  |／|／|
*/

var row = [13]int{0,1,1,1,2,2,2,2,2,3,3,3,4}
var col = [13]int{2,1,2,3,0,1,2,3,4,1,2,3,2}

type wolf struct {
	m [13]int
}

type pair struct {
	first wolf
	second int
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func print_board(board [13]int) {
	fmt.Println("--------------------------")
	fmt.Printf("        [%2d]\n", board[0])
	fmt.Printf("    [%2d][%2d][%2d]\n", board[1], board[2], board[3])
	fmt.Printf("[%2d][%2d][%2d][%2d][%2d]\n", board[4], board[5], board[6], board[7], board[8])
	fmt.Printf("    [%2d][%2d][%2d]\n", board[9], board[10], board[11])
	fmt.Printf("        [%2d]\n", board[12])
	fmt.Println("--------------------------")
}

func main() {
	for scanner.Scan() {
		p1, _ := strconv.Atoi(scanner.Text())
		if p1 == -1 {
			break
		}
		p[0]= p1
		scanner.Scan()
		buf1 := strings.Split(scanner.Text(), " ")
		p2, _ := strconv.Atoi(buf1[0])
		p3, _ := strconv.Atoi(buf1[1])
		p4, _ := strconv.Atoi(buf1[2])
		p[1], p[2], p[3] = p2, p3, p4
		scanner.Scan()
		buf2 := strings.Split(scanner.Text(), " ")
		p5, _ := strconv.Atoi(buf2[0])
		p6, _ := strconv.Atoi(buf2[1])
		p7, _ := strconv.Atoi(buf2[2])
		p8, _ := strconv.Atoi(buf2[3])
		p9, _ := strconv.Atoi(buf2[4])
		p[4], p[5], p[6], p[7], p[8] = p5, p6, p7, p8, p9
		scanner.Scan()
		buf3 := strings.Split(scanner.Text(), " ")
		p10, _ := strconv.Atoi(buf3[0])
		p11, _ := strconv.Atoi(buf3[1])
		p12, _ := strconv.Atoi(buf3[2])
		p[9], p[10], p[11] = p10, p11, p12
		scanner.Scan()
		p13, _ := strconv.Atoi(scanner.Text())
		p[12] = p13
		S := make(map[wolf]struct{})
		st := wolf{}
		for i := 0; i < 13; i++ {
			st.m[i] = p[i]
		}
		Q := make([]pair, 0)
		S[st] = struct{}{}
		Q = append(Q, pair{st, 0})
		yet := true
		for len(Q) > 0 {
			at := Q[0].first
			// print_board(at.m)
			cost := Q[0].second
			Q = Q[1:]
			ok := true
			for i :=1; i < 12; i++ {
				if at.m[i] != i {
					ok = false
				}
			}
			if ok {
				// print_board(at.m)
				yet = false
				fmt.Println(cost)
				break
			}
			now := cost
			for i := 0; i < 13; i++ {
				if at.m[i] != 0 {
					now += abs(row[i]-row[at.m[i]]) + abs(col[i]-col[at.m[i]])
				}
			}
			if now > 20 {
				continue
			}
			for i := 0; i < 13; i++ {
				if at.m[i] == 0 {
					for j := 0; j < 4; j++ {
						if ^g[i][j] != 0 {
							at.m[i], at.m[g[i][j]] = at.m[g[i][j]], at.m[i]
							if _, ok := S[at]; !ok {
								S[at] = struct{}{}
								Q = append(Q, pair{at, cost+1})
							}
							at.m[i], at.m[g[i][j]] = at.m[g[i][j]], at.m[i]
						}
					}
				}
			}
		}
		if yet {
			fmt.Println("NA")
		}
	}
}

C++: #include<iostream>
#include<algorithm>

using namespace std;

#define N 5
#define REP(i, n) for ( int i = 0; i < (int)n; i++ )
#define LIMIT 20

static const int T[12][2] = {{-1, -1}, {1, 1}, {1, 2}, {1, 3}, {2, 0}, {2, 1},
			     {2, 2}, {2, 3}, {2, 4}, {3, 1}, {3, 2}, {3, 3}};
static const int g[N][N] = {{-1, -1, 0, -1, -1}, {-1, 1, 2, 3, -1},
			    {4, 5, 6, 7, 8}, {-1, 9, 10, 11, -1}, {-1, -1, 0, -1, -1}};

class Puzzle{
    public:
    int C[N][N], mdist; //manhatta distance
    Puzzle(){}

    bool swapAdj( int si, int sj, int ti, int tj ){
	if ( ti < 0 || tj < 0 || ti >= N || tj >= N ) return false;
	if ( C[ti][tj] <= 0 ) return false;
	swap(C[ti][tj], C[si][sj]);
	int tti = T[C[si][sj]][0];
	int ttj = T[C[si][sj]][1];
	mdist -= max(tti, ti)-min(tti, ti) + max(ttj, tj)-min(ttj, tj);
	mdist += max(tti, si)-min(tti, si) + max(ttj, sj)-min(ttj, sj);
	return true;
    }

    bool isGoal(){
	REP(i, N) REP(j, N) if ( g[i][j] != C[i][j] ) return false;
	return true;
    }

    int getMD(){ // get initial manhattan distance
	int sum = 0;
	int ti, tj;
	REP(i, 5) REP(j, 5){
	    if ( C[i][j] <= 0 ) continue;
	    ti = T[C[i][j]][0];
	    tj = T[C[i][j]][1];
	    sum += (max(ti, i)-min(ti, i) + max(tj, j) - min(tj, j));
	}
	return sum;
    }
};

int limit;

bool dfs( int depth, Puzzle P ){
    if ( P.isGoal() ) return true;
    if ( depth + P.getMD() > limit ) return false;

    static const int di[4] = {0, -1, 0, 1};
    static const int dj[4] = {1, 0, -1, 0};

    REP(i, N) REP(j, N){
	if ( P.C[i][j] != 0 ) continue;
	REP(r, 4){
	    Puzzle v = P;
	    if ( !v.swapAdj(i, j, i+di[r], j+dj[r]) ) continue;
	    if ( dfs( depth + 1, v ) ) return true;
	}
    }

    return false;
}

int idp(Puzzle source){
    for ( limit = 0; limit <= LIMIT; limit++ ){
	source.mdist = source.getMD();
	if ( dfs(0, source) ) return limit;
    }
    return INT_MAX;
}

int main(){
    Puzzle P;
    int top;

    while(1){
	cin >> top;
	if ( top == -1 ) break;
	REP(j, N) P.C[0][j] = -1;
	P.C[0][2] = top;
	for(int i = 1; i < N; i++) REP(j, N){
	    if ( (i == 1 || i == 3) && (j == 0 || j == 4 ) ) P.C[i][j] = -1;
	    else if ( i == 4 && j != 2 ) P.C[i][j] = -1;
	    else cin >> P.C[i][j];
	}

	int cost = idp(P);
	if ( cost == INT_MAX ) cout << "NA" << endl;
	else cout << cost << endl;	
    }

    return 0;
}

C++: #include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
template<class T>
using Table = vector<vector<T>>;
const ld eps=1e-9;

//// < "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\a.txt" > "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\b.answer"

vector<vector<int>>ans = vector<vector<int>>{
	vector<int>{-1,-1,-1,-1,-1,-1,-1},
	vector<int>{-1,-1,-1,0,-1,-1,-1},
	vector<int>{-1,-1,1,2,3,-1,-1},
	vector<int>{-1,4,5,6,7,8,-1},
	vector<int>{-1,-1,9,10,11,-1,-1},
	vector<int>{-1,-1,-1,0,-1,-1,-1},
	vector<int>{-1,-1,-1,-1,-1,-1,-1},
};

#include<unordered_map>
class HashVI {  // ???????????\??¢??°???????????§??????
public:
	size_t operator()(const vector<int> &x) const {
		const int C = 997;      // ?´???°
		size_t t = 0;
		for (int i = 0; i != x.size(); ++i) {
			t = t * C + x[i];
		}
		return t;
	}
	size_t operator()(const vector<vector<int>> &x) const {
		const int C = 997;      // ?´???°
		size_t t = 0;
		for (int i = 0; i != x.size(); ++i) {
			for (int j = 0; j < x[i].size(); ++j) {
				t = t * C + x[i][j];
			}
		}
		return t;
	}
};
int dx[] = { -1,0,1,0 };
int dy[] = { 0,1,0,-1 };
int aaa=21;
void solve(vector<vector<int>>&start,const int turn ) {
	if (aaa <= turn)return;
	if (start == ans) {
		aaa = min(aaa, turn);
	}
	else {
		for (int i = 1; i < 6; ++i) {
			for (int j = 1; j < 6; ++j) {
				if (start[i][j] == 0) {
					for (int way = 0; way < 4; ++way) {
						if (start[i + dy[way]][j + dx[way]]>0) {
							swap(start[i][j],start[i + dy[way]][j + dx[way]]);
							if (start == ans) {
								aaa = min(aaa, turn);
							}
							else {

								solve(start, turn+1);
							}
							swap(start[i][j], start[i + dy[way]][j + dx[way]]);
						}
					}
				}
			}
		}
	}
	
}

int main() {
	while (1) {
		int a; cin >> a;
		if (a == -1)break;
		vector<vector<int>>puzzle(7, vector<int>(7,-1));
		puzzle[1][3] = a;
		for (int i = 2; i <= 5; ++i) {
			for (int j = 3 - (2-(abs(i - 3))); j <= 3 + (2-abs(i - 3)); ++j) {
				cin >> puzzle[i][j];
			}
		}
		if (puzzle == ans) {
			cout << 0 << endl;
		}
		else {

			solve(puzzle, 1);
			if (aaa == 21)cout << "NA" << endl;
			else cout << aaa << endl;
		}
	}
	return 0;
}