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(now[0]+now[1] < 20)
							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>
using namespace std;
  
typedef long long int64;
const int INF = 1 << 30;
  
vector< int > edge[13];
map< string, int > memo;
 
bool back(string str, int cnt){ //枝刈り大事だな
  int X[]={ 2, 1, 2, 3, 0, 1, 2, 3, 4, 1, 2, 3, 2};
  int Y[]={ 0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4};

  int diff = 0;
  for(int i = 0; i < 13; i++){
   
    if(str[i] != '0'){
      int pos = (str[i] >= 'A' ? str[i] - 'A' : str[i] - '0');
      diff += abs( X[pos] - X[i]) + abs( Y[pos] - Y[i]);
    }
  }
  return diff + cnt > 20;
}
 
 
int bfs(string mas){
 
  queue< string > que;
  map< string , int > used;
  que.push( mas );
  memo[mas] = 0;
  while(!que.empty()){
 
    string p = que.front(); que.pop();
    if(back( p, memo[p])) continue;
    if(p == "0123456789AB0") return memo[p];
 
    for(int i = 0; i < 13; i++){
      if(p[i] == '0') {
        for(int j = 0; j < edge[i].size(); j++){
          string next = p;
          swap( next[i], next[edge[i][j]]);
          if(memo.find(next) != memo.end()) continue;
          que.push( next );
          memo[next] = memo[p] + 1;
        }
      }
    }
  }
  return -1;
}
 
int main(){
  vector< int > mas(13);
 
  edge[0].push_back(2);
  edge[1].push_back(2); edge[1].push_back(4);
  edge[2].push_back(0); edge[2].push_back(1); edge[2].push_back(3); edge[2].push_back(6);
  edge[3].push_back(2); edge[3].push_back(7);
  edge[4].push_back(5);
  edge[5].push_back(1); edge[5].push_back(4); edge[5].push_back(6); edge[5].push_back(9);
  edge[6].push_back(2); edge[6].push_back(5); edge[6].push_back(7); edge[6].push_back(10);
  edge[7].push_back(3); edge[7].push_back(6); edge[7].push_back(8); edge[7].push_back(11);
  edge[8].push_back(7);
  edge[9].push_back(5); edge[9].push_back(10);
  edge[10].push_back(6); edge[10].push_back(9); edge[10].push_back(11); edge[10].push_back(12);
  edge[11].push_back(7); edge[11].push_back(10);
  edge[12].push_back(10);
 
  while(cin >> mas[0], mas[0] != -1){
    for(int i = 1; i < 13; i++){
      cin >> mas[i];
    }
 
    string start = "";
    for(int i = 0; i < 13; i++){
      if(mas[i] >= 10) start += (char)(mas[i] - 10 + 'A');
      else start += mas[i] + '0';
    }
    int ret = bfs(start);
    if(~ret) cout << ret << endl;
    else cout << "NA" << endl;
 
    memo.clear();
  }
}