Go: ///
// File:  0558.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:58:45 2018
//
package main

import (
	"fmt"
	"strconv"
	"strings"
)

type pos struct {
	x, y int
}

var H, W, N int
var graph [][]string

func wfs(p pos, index int) (int, pos) {
	var q []pos
	dists := make([][]int, H)
	for i := range dists {
		dists[i] = make([]int, W)
	}

	q = append(q, p)
	for len(q) > 0 {
		p := q[0]
		dist := dists[p.x][p.y]
		q = q[1:]

		for _, d := range []pos{{-1, 0}, {1, 0}, {0, -1}, {0, 1}} {
			x := p.x + d.x
			y := p.y + d.y
			if 0 <= x && x < H && 0 <= y && y < W && graph[x][y] != "X" && dists[x][y] == 0 {
				dists[x][y] = dist + 1
				q = append(q, pos{x, y})
			}
		}
	}

	for i := range graph {
		for j := range graph[i] {
			if graph[i][j] == strconv.Itoa(index) {
				return dists[i][j], pos{i, j}
			}
		}
	}

	panic("not found")
}

func main() {
	fmt.Scan(&H, &W, &N)

	var start pos

	graph = make([][]string, H)
	for i := range graph {
		var s string
		fmt.Scan(&s)
		graph[i] = strings.Split(s, "")
		for j := range graph[i] {
			if graph[i][j] == "S" {
				start.x = i
				start.y = j
			}
		}
	}

	count := 0
	for i := 1; i <= N; i++ {
		c, s := wfs(start, i)
		start = s
		count += c
	}

	fmt.Println(count)
}

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

#define pb(n) push_back(n)
#define fi first
#define se second
#define X real()
#define Y imag()
#define value(x,y,w,h) (x >= 0 && x < w && y >= 0 && y < h)
#define all(r) (r).begin(),(r).end()
#define gsort(st,en) sort((st),(en),greater<int>())
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout<<#x<<": "<<x<<endl
#define fcout(n) cout<<fixed<<setprecision((n))
#define scout(n) cout<<setw(n)
#define vary(type,name,size,init) vector< type> name(size,init)

#define rep(i,n) for(int i = 0; i < (int)(n);++i)
#define REP(i,a,b) for(int i = (a);i < (int)(b);++i)
#define repi(it,array) for(auto it = array.begin(),end = array.end(); it != end;++it)
#define repa(n,array) for(auto &n :(array))

using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using dict = map<string,int>;
using comd = complex<double>;
using pii = pair<int,int> ;

constexpr int imax = ((1<<30)-1)*2+1 ;
constexpr int inf = 10000000;
constexpr double PI = acos(-1.0) ;
double eps = 1e-10 ;
const int dy[] = {-1,0,1,0};
const int dx[] = {0,-1,0,1};

int N,W,H,S;
vector<vector<int>> maps;
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  char c;
  int n = 0;
  cin >> W >> H >> N;
  char area[H][W];
  maps = vector<vector<int>>(H,vector<int>(W,-1));
  pii pos;
  rep(i,W){
    rep(j,H){
      cin >> c ;
      area[j][i] = c;
      if(c == 'S'){
        pos = make_pair(j,i);
        ++n;
      }
    }
  }
  queue<pii> q;
  q.push(pos);
  maps[pos.fi][pos.se] = 0;
  n = 1;
  int ans = 0;
  for(n = 1; n < N+1;++n){
    maps = vector<vector<int>>(H,vector<int>(W,-1));
    q = queue<pii>();
    q.push(pos);
    maps[pos.fi][pos.se] = 0;
    while(!q.empty()){
      pii p = q.front();q.pop();
      rep(i,4){
        int x = p.fi + dx[i],y = p.se+dy[i];
        if(value(x,y,H,W)){
          if(area[x][y] - '0' == n){
            ans += maps[p.fi][p.se] + 1;
            pos = make_pair(x,y);
            q = queue<pii>();
            break;
          }
          else if(area[x][y] != 'X' && (maps[x][y] >= maps[p.fi][p.se]+1 || maps[x][y] == -1)){
            q.push(make_pair(x,y));
            maps[x][y] = maps[p.fi][p.se] +1 ;
          }
        }
      }
    }
  }
  cout << ans << endl;
  return 0;
}

C++: #include <iostream>
#include <queue>
using namespace std;
int w, h, n;
char map[1024][1024];
// 各点到当前工厂的距离
int d[1024][1024];
const int direction[4][2] = {
	{ -1, 0 },
	{ 1, 0 },
	{ 0, -1 },
	{ 0, 1 },
};

int factory[16][2];
typedef pair<int, int> P;



//************************************
// Method:    bfs
// FullName:  bfs
// Access:    public 
// Returns:   int
// Qualifier:
// Parameter: const int & sx 起点x
// Parameter: const int & sy 起点y
// Parameter: const int & gx 终点x
// Parameter: const int & gy 终点y
//************************************
int bfs(const int& sx, const int& sy, const int& gx, const int& gy)
{
	//memset(d, -1, sizeof(d));
	for (int i = 0; i < h; ++i)
	{
		for (int j = 0; j < w; ++j)
		{
			d[j][i] = -1;
		}
	}
	queue<P> que;
	que.push(P(sx, sy));
	d[sx][sy] = 0;
	while (que.size())
	{
		const P p = que.front(); que.pop();
		// 如果是终点就结束
		if (p.first == gx && p.second == gy)
		{
			break;
		}

		// 四方向漫游
		for (int i = 0; i < 4; ++i)
		{
			int nx = p.first + direction[i][0];
			int ny = p.second + direction[i][1];
			// 是否可以移动，并且该点没有访问过
			if (0 <= nx && nx < w && 0 <= ny && ny < h && map[nx][ny] != 'X' && d[nx][ny] == -1)
			{
				que.push(P(nx, ny));
				d[nx][ny] = d[p.first][p.second] + 1;
			}
		}
	}

	return d[gx][gy];
}

///////////////////////////SubMain//////////////////////////////////
int main(int argc, char *argv[])
{

	cin >> h >> w >> n;
	for (int i = 0; i < h; ++i)
	{
		for (int j = 0; j < w; ++j)
		{
			cin >> map[j][i];
		}
	}

	for (int i = 0; i < h; ++i)
	{
		for (int j = 0; j < w; ++j)
		{
			if (map[j][i] == 'S')
			{
				factory[0][0] = j;
				factory[0][1] = i;
				map[j][i] = '.';
			}
			else if (isdigit(map[j][i]))
			{
				int index = map[j][i] - '0';
				factory[index][0] = j;
				factory[index][1] = i;
			}
		}
	}

	int step = 0;
	for (int i = 0; i < n; ++i)
	{
		// 按顺序吃遍中华
		step += bfs(factory[i][0], factory[i][1], factory[i + 1][0], factory[i + 1][1]);
	}
	
	cout << step << endl;

	return 0;
}