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 <algorithm>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <vector>

using namespace std;

#define reps(i,f,n) for(int i=f; i<int(n); ++i)
#define rep(i,n) reps(i,0,n)

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

const int INF = 1001001001;
const ll FINAL = 0x0ba9876543210ll;

struct Data
{
	ll s;
	int d;
	bool f;
	Data(ll s, int d, bool f) : s(s), d(d), f(f) {}
};

int bfs(ll init)
{
	if(init == FINAL)
		return 0;
	
	const int move[13][5] = {
		{2, -1},
		{2, 5, -1},
		{0, 1, 3, 6, -1},
		{2, 7, -1},
		{5, -1},
		{1, 4, 6, 9, -1},
		{2, 5, 7, 10, -1},
		{3, 6, 8, 11, -1},
		{7, -1},
		{5, 10, -1},
		{6, 9, 11, 12, -1},
		{7, 10, -1},
		{10, -1}
	};
	
	set<ll> visited[2];
	queue<Data> Q;
	Q.push(Data(init, 0, false));
	Q.push(Data(FINAL, 0, true));
	visited[0].insert(init);
	visited[1].insert(FINAL);
	int now[2] = {0};
	
	while(!Q.empty()){
		Data data = Q.front();
		Q.pop();
		now[data.f] = data.d + 1;

		for(int i=0, cnt=2; cnt; ++i){
			if(((data.s>>(i*4)) & 0xfll) == 0){
				for(int j=0; move[i][j]!=-1; ++j){
					ll next = data.s;
					next &= ~((0xfll << (i*4)) | (0xfll << (move[i][j]*4)));
					next |= ((data.s >> (move[i][j]*4)) & 0xfll) << (i*4);
					
					if(visited[!data.f].find(next) != visited[!data.f].end())
						return now[0] + now[1];

					if(visited[data.f].find(next) == visited[data.f].end()){
						visited[data.f].insert(next);
						if(data.d < 10)
							Q.push(Data(next, data.d+1, data.f));
					}
				}
				--cnt;
			}
		}
	}
	return -1;
}

int main()
{
	for(;;){
		int input[13];
		rep(i, 13){
			scanf("%d", &input[i]);
			if(input[i] == -1)
				return 0;
		}

		ll init = 0;
		rep(i, 13)
			init = (init << 4) | input[12-i];

		int ans = bfs(init);
		if(ans == -1 || ans > 20)
			puts("NA");
		else
			printf("%d\n", ans);
	}
}

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 solve(const vector<vector<int>>&start) {
	if (start == ans)return 0;
	set<vector<vector<int>>>mp;
	mp.emplace(start);
	for (int t = 0; t < 20; ++t) {
		set<vector<vector<int>>>nextmp;
		for (auto m : mp) {
			for (int i = 1; i < 6; ++i) {
				for (int j = 1; j < 6; ++j) {
					if (m[i][j] == 0) {
						for (int way = 0; way < 4; ++way) {
							if (m[i + dy[way]][j + dx[way]]>0) {
								swap(m[i][j], m[i + dy[way]][j + dx[way]]);
								if (m == ans)return t + 1;
								nextmp.emplace(m);
								swap(m[i][j], m[i + dy[way]][j + dx[way]]);
							}
						}
					}
				}
			}
		}
		mp = nextmp;
	}
	return -1;
}

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];
			}
		}
		int ans = solve(puzzle);
		if (ans == -1)cout << "NA" << endl;
		else cout << ans << endl;
	}
	return 0;
}