# Poj Solution 3026

```http://poj.org/problem?id=3026

import java.io.PrintWriter;
import java.util.Queue;
import java.util.Scanner;

public class Main {
static class Point{
int x,y,step;
int result = 1;
char c;
public Point(int x, int y, char c){
this.x = x;
this.y = y;
this.c = c;
step = 1;
}
public Point(int x, int y,int step, char c){
this.x = x;
this.y = y;
this.c = c;
this.step = step;
}
@Override
public int hashCode() {
if(result != 1){
return result;
}
final int prime = 31;
result = 1;
result = prime * result + c;
result = prime * result + x;
result = prime * result + y;
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
Point other = (Point) obj;
if (c != other.c)
return false;
if (x != other.x)
return false;
if (y != other.y)
return false;
return true;
}

}
static int[][] all = new int[150][150];
static int[] DX = {0,-1,0,1};//e n w s
static int[] DY = {-1,0,1,0};
public static void main(String[] args) {
Scanner scn = new Scanner(System.in);

PrintWriter out = new PrintWriter(System.out);

int n = scn.nextInt(),x,y;
int num;//S �� A ����
char[][] data = new char[101][101];
int[][] table = new int[101][101];
Point[] points = new Point[101];
Point point;
String str;
while(n-- > 0){
x = scn.nextInt();
y = scn.nextInt();

scn.nextLine();
for(int i = 0; i < y; i++){
str = scn.nextLine();
data[i] = str.toCharArray();
}
//�õ�������������points������4
num = getNum(data,y,x,points);
for(int i = 0; i < num; i++){
bfs(data,table,points[i]);
}
out.println(prim(table, num));
}
out.flush();
}
private static void bfs(char[][] data, int[][] table, Point point) {
int x,y,nx,ny;
int px = all[point.x][point.y];
int[][] visted = new int[150][150];
while(!queue.isEmpty()){
point = queue.poll();
x = point.x;
y = point.y;
for(int i = 0; i < 4; i++){
nx = x + DX[i];
ny = y + DY[i];
if(data[nx][ny] == '#'){
continue;
}
if(visted[nx][ny] == 1){
continue;
}
visted[nx][ny] = 1;
if(data[nx][ny] == 'A' || data[nx][ny] == 'S'){
table[px][all[nx][ny]] = point.step;
}
}
}
}

/**
* �õ� y �� s ����
* @param data
* @param y
* @param x
* @return
*/
private static int getNum(char[][] data, int x, int y,Point[] points) {
int num = 0;
char c;
for(int i = 0; i < x; i++){
for(int j = 0; j < y; j++){
c = data[i][j];
if(c == 'A' || c == 'S'){
all[i][j] = num;
points[num] = new Point(i,j,c);
num++;
}
}
}
return num;
}
public static int prim(int[][] table, int n) {

int[] lowcost = new int[n];
boolean[] s = new boolean[n];
int sum = 0;
s[0] = true;// �ӵ�һ��λ�ÿ�ʼ
for (int i = 1; i < n; i++) {
lowcost[i] = table[0][i];
s[i] = false;
}
// �ҵ� j - s �е���СȨ��
for (int i = 1; i < n; i++) {
int min = Integer.MAX_VALUE;
int j = 1;
for (int k = 1; k < n; k++) {
if ((lowcost[k] < min) && (!s[k])) {
min = lowcost[k];
j = k;
}
}
s[j] = true;// ���뵽j ���뵽 s ������4
// sum += min;
for (int k = 1; k < n; k++) {
if (table[j][k] < lowcost[k] && (!s[k])) {
lowcost[k] = table[j][k];
}
}
}

for (int i = 0; i < n; i++) {
sum += lowcost[i];
}
return sum;
}
}

```
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