protohackers/cmd/meanstoanend/main.go

61 lines
967 B
Go

package main
import (
"encoding/binary"
"io"
"log"
"net"
"protohackers/pkg/conn"
)
func main() {
err := conn.StartSimpleTCP(meansToAnEnd)
if err != nil {
log.Fatalln(err)
}
}
func meansToAnEnd(c net.Conn) {
defer c.Close()
var ledger = make(map[int32]int32)
buf := make([]byte, 9)
for {
if _, err := io.ReadFull(c, buf); err != nil {
return
}
if _, err := c.Write(process(buf, ledger)); err != nil {
return
}
}
}
func process(buf []byte, ledger map[int32]int32) []byte {
i1, i2 := int32(binary.BigEndian.Uint32(buf[1:5])), int32(binary.BigEndian.Uint32(buf[5:]))
switch buf[0] {
case 'I':
ledger[i1] = i2
case 'Q':
var c int64
var t int64
for k, v := range ledger {
if i1 <= k && k <= i2 {
t += int64(v)
c++
}
}
if c == 0 {
c = 1 /* Can't divide by zero! */
}
mean := t / c
r := make([]byte, 4)
binary.BigEndian.PutUint32(r, uint32(mean))
return r
default:
return nil
}
return nil
}