面试汇总

[jinhailang]

面试汇总

这几年经历过不少面试，记录下来，偶尔看看，每次体验应该都会不一样吧。

某电商/平台容器调度

在线编程题

由于时间有限，写的比较仓促，基本满足要求。

• 请实现两个线程，使之交替打印1-100，如：两个线程分别为：Printer1+和+Printer2，最后输出结果为：

Printer1--1
Printer2--2
Printer1--3
Printer2--4

package main

import (
	"fmt"
	"time"
)

const (
	total = 100
)

//Printer1

func Printer1(a, b chan int) {
	for i := range a {
		if i > 100 {
			return
		}

		fmt.Printf("Printer1--%d\r\n", i)
		b <- i + 1
	}
}

func Printer2(a, b chan int) {
	for i := range a {
		if i > 100 {
			return
		}

		fmt.Printf("Printer2--%d\r\n", i)
		b <- i + 1
	}
}

func main() {
	a := make(chan int)
	b := make(chan int)

	go Printer1(a, b)
	go Printer2(b, a)

	a <- 0

	time.Sleep(time.Millisecond * 10) //阻塞

	close(a)
	close(b)

	fmt.Printf("exit\n")
}

• 设计并实现一个程序，达到和下面的 shell 命令相同的效果：
  cat /home/admin/logs/data.log | grep alibaba | sort | uniq -c | sort -nr

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"sort"
	"strings"
)

const (
	LOG = "/Users/jinhailang/Desktop/test.txt" //"/home/admin/logs/data.log"
)

func cat(path, key string) ([]string, error) {
	var ss []string

	fi, err := os.Open(LOG)
	if err != nil {
		fmt.Printf("Open error: %v\n", err)
		return nil, err
	}

	defer fi.Close()

	br := bufio.NewReader(fi)
	for {
		a, _, c := br.ReadLine()
		if c == io.EOF {
			break
		}

		s := string(a)
		if strings.Contains(s, key) {
			ss = append(ss, s)
		}
	}

	fmt.Println("ss: ", ss)

	return ss, nil
}

func uniq(ss []string) map[string]int {
	mp := make(map[string]int)

	for _, s := range ss {
		count, ok := mp[s]
		if ok {
			count++
			mp[s] = count
		} else {
			mp[s] = 1
		}
	}

	return mp
}

type kv struct {
	K string
	V int
}

type kvs []kv

func (p kvs) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
func (p kvs) Len() int           { return len(p) }
func (p kvs) Less(i, j int) bool { return p[i].V < p[j].V }

func sort_nr(mp map[string]int) []kv {
	p := make(kvs, len(mp))
	i := 0
	for k, v := range mp {
		p[i] = kv{k, v}
		i = i + 1
	}

	sort.Sort(p)

	return p
}

func main() {
	ss, _ := cat(LOG, "alibaba")

	sort.Strings(ss)
	fmt.Println("sort after ss: ", ss)

	mp := uniq(ss)
	fmt.Println("uniq after mp: ", mp)

	kk := sort_nr(mp)
	fmt.Println("sort_nr after kk: ", kk)

	fmt.Println("exit.")
}