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 <cstdio>
#include <queue>
#include <climits>
using namespace std;

const int MAX_H = 1000;
const int MAX_W = 1000;
const int MAX_N = 10;

const int dx[] = {0, 1, 0, -1};
const int dy[] = {-1, 0, 1, 0};

typedef struct {
	int x, y;
} node;
node makeNode(int x, int y) {
	node n = {x, y};
	return n;
}

int w, h, n;
// 入力されたフィールド (W * H)
char field[MAX_H][MAX_W];
// 各地点までのステップ数，未到達なら INT_MAX
int step[MAX_H][MAX_W];

int bfs(int startX, int startY, int goalX, int goalY) {
	queue<node> que;
	que.push(makeNode(startX, startY));
	step[startY][startX] = 0;
	while (!que.empty()) {
		node current = que.front();
		que.pop();
		if (current.x == goalX && current.y == goalY) {
			return step[goalY][goalX];
		}
		int nextStep = step[current.y][current.x] + 1;
		for (int i = 0; i < 4; i++) {
			int nextX = current.x + dx[i];
			int nextY = current.y + dy[i];
			if (0 <= nextX && nextX < w && 0 <= nextY && nextY < h
					&& field[nextY][nextX] != 'X' && step[nextY][nextX] == INT_MAX) {
				que.push(makeNode(nextX, nextY));
				step[nextY][nextX] = nextStep;
			}
		}
	}
	return INT_MAX;
}

int main () {
	while (scanf("%d %d %d", &h, &w, &n) != EOF) {
		int startX, startY;
		// 入力しながらスタートの座標を探す
		for (int i = 0; i < h; i++) {
			scanf("%s", field[i]);
			for (int j = 0; j < w; j++) {
				if (field[i][j] == 'S') {
					startX = j;
					startY = i;
				}
			}
		}
		
		// 工場を順番に回って合計ステップを計算する
		int ans = 0;
		for (int i = 1; i <= n; i++) {
			// step を INT_MAX で初期化しながらゴールの座標を探す
			int goalX, goalY;
			for (int j = 0; j < h; j++) {
				for (int k = 0; k < w; k++) {
					step[j][k] = INT_MAX;
					if (field[j][k] == '0' + i) {
						goalX = k;
						goalY = j;
					}
				}
			}
			
			ans += bfs(startX, startY, goalX, goalY);
			
			startX = goalX;
			startY = goalY;
		}
		
		printf("%d\n", ans);
	}
	return 0;
}