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 <iostream>
#include <queue>
#include <algorithm>
using namespace std;
int m,n,t;
int cnt;
char c;
char map[1010][1010];
bool vis[1010][1010];
struct node
{
	int x,y;
	int step;
}start;
int way[4][2] = {{-1,0},{0,1},{1,0},{0,-1}};
void bfs()
{
	queue <node> abc;
	abc.push(start);
	while(!abc.empty())
	{
		node k = abc.front(); 
		abc.pop();
		if(map[k.y][k.x] == c)
		{
			cnt+=k.step;
			k.step = 0;
			memset(vis,0,sizeof(vis));
			while(!abc.empty())
			abc.pop();
			c++;
			t--;
		}
		if(t==0)
		{
			return;
		}
		for(int i = 0;i<4;i++)
		{
			int dx = k.x+way[i][0];
			int dy = k.y+way[i][1];
			if(dx>=0 && dx<n && dy>=0 && dy<m && !vis[dy][dx] &&map[dy][dx]!='X')
			{
				node temp;
				temp.x = dx;
				temp.y = dy;
				temp.step = k.step+1;
				abc.push(temp);
				vis[dy][dx]=1;
			}
		}
	}	
} 
int main()
{
	while(cin >> m >> n >> t)
	{
		cnt = 0;
		c = '1';
		memset(vis,0,sizeof(vis));
		memset(map,0,sizeof(map));
		for(int i = 0;i<m;i++)
		{
			for(int j = 0;j<n;j++)
			{
				cin >> map[i][j];
				if(map[i][j] == 'S')
				{
					start.x = j;
					start.y = i;
					start.step = 0;
				}
			}
		}
		bfs();
		cout << cnt << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<stack>
#include<queue>
#include<string>
#include<vector>
#define rep(i,a,n) for(int i=a;i<n;i++)
#define per(i,n,a) for(int i=n;i>a;i--)
#define mem0(x) memset(x,0,sizeof(x))
#define memff(x) memset(x,0xff,sizeof(x))
#define INF 100000000
using namespace std;
typedef pair<int,int> P;
typedef long long LL;
int w,h,n;
int sw[15],sh[15];
char maze[1024][1024];
int d[1024][1024];
int dw[4]={0,1,0,-1},dh[4]={1,0,-1,0};
int BFS(int sw,int sh,int gw,int gh)
{
    queue<P> que;
    for(int i=1;i<=w;i++)
    {
        for(int j=1;j<=h;j++)
        {
            d[i][j]=INF;
        }
    }
    que.push(P(sw,sh));
    d[sw][sh]=0;
    while(que.size())
    {
        P p=que.front();
        que.pop();
        if(p.first==gw&&p.second==gh)break;
        for(int i=0;i<4;i++)
        {
            int nw=p.first+dw[i],nh=p.second+dh[i];
            if(1<=nw&&nw<=w&&1<=nh&&nh<=h&&maze[nw][nh]!='X'&&d[nw][nh]==INF)
            {
                que.push(P(nw,nh));
                d[nw][nh]=d[p.first][p.second]+1;
            }
        }
    }
    return d[gw][gh];
}
int main()
{
    //freopen("input.in","r",stdin);
    while(cin>>w>>h>>n)
    {
        int ans=0;
        for(int i=1;i<=w;i++)
        {
            for(int j=1;j<=h;j++)
            {
                cin>>maze[i][j];
                if(maze[i][j]=='S')
                {
                    sw[0]=i;sh[0]=j;
                }
            }
        }
        for(int i=1;i<=w;i++)
        {
            for(int j=1;j<=h;j++)
            {
                if(maze[i][j]>48&&maze[i][j]<58)
                {
                    sw[maze[i][j]-48]=i;
                    sh[maze[i][j]-48]=j;
                }
            }
        }
        for(int i=0;i<=n-1;i++)
        {
            ans+=BFS(sw[i],sh[i],sw[i+1],sh[i+1]);
        }
        cout<<ans<<endl;
    }
    return 0;
}

C++: #include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <stack>
#include <array>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <functional>
#include <iomanip>
#include <numeric>
#include <assert.h>
#include <bitset>

#define MOD 1000000007
#define INF 11234567890
#define in std::cin
#define out std::cout
#define rep(i,N) for(LL i=0;i<N;++i)
typedef long long int LL;
typedef std::pair<LL, LL> P;
struct edge { LL to, cost; };

LL H, W, N;
std::string field[1123];
LL Sx, Sy, xy[11];
LL ans;

LL d[1123456];
std::vector<edge>G[1123456];
void dijkstra(LL s)
{
	std::priority_queue<P, std::vector<P>, std::greater<P>>que;
	std::fill(d, d + H * W + 1, INF);
	d[s] = 0;
	que.push(P(0, s));
	while (!que.empty())
	{
		P p = que.top(); que.pop();
		LL v = p.second;
		if (d[v] < p.first) { continue; }
		rep(i, G[v].size())
		{
			edge e = G[v][i];
			if (d[e.to] > d[v] + e.cost)
			{
				d[e.to] = d[v] + e.cost;
				que.push(P(d[e.to], e.to));
			}
		}
	}
}

int main()
{
	try {
		in >> H >> W >> N;
		rep(i, H) { in >> field[i]; }

		rep(h, H)
		{
			rep(w, W)
			{
				if (field[h][w] == 'X') { continue; }
				if (field[h][w] == 'S') { Sx = h; Sy = w; }
				if (field[h][w] != '.') { xy[field[h][w] - '0'] = h*W + w; }
				if (h < H - 1)
				{
					if (field[h + 1][w] != 'X')
					{
						G[h*W + w].push_back({ (h + 1)*W + w,1 });
						G[(h + 1)*W + w].push_back({ h*W + w,1 });
					}
				}
				if (w < W - 1)
				{
					if (field[h][w + 1] != 'X')
					{
						G[h*W + w].push_back({ h*W + (w + 1),1 });
						G[h*W + (w + 1)].push_back({ h*W + w,1 });
					}
				}
			}
		}
		//dijkstra(Sx*W + Sy);
		//rep(i, N)
		//{
		//	ans += d[xy[i + 1]];
		//	dijkstra(xy[i + 1]);
		//}

		out << ans << std::endl;
		return 0;
	}
	catch (std::bad_alloc) { return 0; }
	catch (...) { return 0; }
}