图的最小生成树2

要用n-1条边将n个顶点连接起来，那么每个顶点都必须至少有一条边与它相连。我们可以随便选择一个顶点开始，找出它的最短的边。例如1号顶点有2条边（1-2,1-3）在这两条边中我们选择一条最短的边(1-2)，此时我们认为1号顶点和2号顶点已经连通，我们接着在1号顶点和2号顶点的边中找出最短的边（1-3），此时1,2,3号顶点已经连通，以此类推我们可以将整个图连通

int[][] arrs = new int[6][6];
int[] dis = new int[6];
int[] book = new int[6];

private void initArrs() {
for (int i = 0; i <= 5; i++) {
for (int j = 0; j <= 5; j++) {
if (i == j) {
arrs[i][j] = 0;
} else {
arrs[i][j] = 999;
}
}
}

arrs[1][3] = 11;
arrs[3][1] = 11;

arrs[2][4] = 13;
arrs[4][2] = 13;

arrs[3][5] = 3;
arrs[5][3] = 3;

arrs[4][5] = 4;
arrs[5][4] = 4;

arrs[1][2] = 6;
arrs[2][1] = 6;

arrs[3][4] = 7;
arrs[4][3] = 7;

arrs[0][1] = 1;
arrs[1][0] = 1;

arrs[2][3] = 9;
arrs[3][2] = 9;

arrs[0][2] = 2;
arrs[2][0] = 2;

for (int i = 0; i <= 5; i++) {
dis[i] = arrs[0][i];
}
}

@Test
public void testSmallTree() {
initArrs();

int sum = 0, count = 0;
book[0] = 1;

while (count < 5) {
int min = 999;
int j = -1;

for (int i = 0; i <= 5; i++) {
if (dis[i] < min && book[i] == 0) {
min = dis[i];
j = i;
}
}

sum += dis[j];
count++;
book[j] = 1;

for (int i = 0; i <= 5; i++) {
if (dis[i] > arrs[j][i] && book[i] == 0) {
dis[i] = arrs[j][i];
}
}
}

System.out.println(sum);
}