问题描述
我有一个带有buildings表的数据库，该表包含类型为coordinate的{{1}}列。为了阅读坐标，我编写了以下代码：
GEOMETRY(POINT,4326)然后，我收到以下错误：
rows,err := db.pool.Query(context.Background(),`select "uuid","coordinate" from "building"`)
defer rows.Close()
for rows.Next() {
var uuid pgtype.UUID
var coordinate postgis.Point
err := rows.Scan(&uuid,&coordinate)
if err != nil {
return err
}
log.Println("~~~",coordinate.X,coordinate.Y)
}
先谢谢您。任何建议都会有所帮助。
解决方法
01234567
acbbaacc k = 2
0 a heap: (0 a)
1 c heap: (1 c) <- (0 a)
2 b heap: (2 b) <- (1 c) <- (0 a)
3 b kth instance,remove (2 b)
heap: (1 c) <- (0 a)
leftmost instance of b is to the
right of the heap root.
check root + 1 = 2,which points
to a new valid substring,add the
substring to the queue
queue: (2,3)
result: 1 + 0 = 1
4 a kth instance,remove (0 a)
heap: (1 c)
queue: (2,3)
result: 1
leftmost instance of a is left
of the heap root so continue
5 a (k+1)th instance,move left border
of the window to index 1
heap: (1 c)
queue: (2,3)
result: 1
(5 a) is now the kth instance of
a and its leftmost instance is to
the right of the heap root.
check root + 1 = 2,which points
to a valid substring in the queue,add new substring to queue
heap: (1 c)
queue: (2,3) -> (4,5)
result: 1 + 1 + 1 = 3
6 c kth instance,remove (1 c)
heap: empty
add new substring to queue
queue: (1) -> (2,5) -> (6)
(for simplicity,the queue here
is not labeled; labels may be needed
for the split intervals)
result: 3 + 1 + 0 = 4
7 c (k+1)th instance,move left border
of the window to index 2,update queue
heap: empty
queue: (2,5)
result: 4
(7 c) is now the kth instance of c
heap: empty
add new substring to queue
queue: (2,5) -> (6,7)
result: 4 + 1 + 2 = 7