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几个golang的面试编程题目

前几天出去面试了，有几个编程现场编程题目，我这里记录一下:

字符串翻转

  • 方法1
// 非常低的效率
func reverse(s string)string{
	var buffer = []rune(s)
	var arr []rune
	for index := range buffer{
		arr = append([]rune{buffer[index]},arr ...)
	}
	return string(arr)
}
  • 方法2
func reverse(s string)string{
	var n string
	for _,v := range s{
		n = string(v)+n
	}
	return n
}

10个goroutine分别打印 1, 2, 3 … 10

  • 方法1
package main

import "sync"

var wg sync.WaitGroup

func fx(n int){
	defer wg.Done()
	println(n)
}


func main(){
	for i := 1 ;i <=10;i++{
		wg.Add(1)
		go fx(i)
	}
	wg.Wait()
}
  • 方法2
package main

import "sync"

// 生产者消费原理
var wg sync.WaitGroup
func fx(c chan int){
	defer wg.Done()
	value , ok := <- c
	if !ok {
		return
	}
	println(value)
	if value == 10{
		close(c)
		return
	}
	c<-value+1
}

func main(){
	var c = make(chan int)
	for i := 0 ;i < 10 ;i++{
		wg.Add(1)
		go fx(c)
	}
	c<-1
	wg.Wait()
}

前序遍历二叉树

type Node struct{
	Value int
	Left *Node
	Right *Node
}

func loop(tree *Node){
	if tree == nil{
		return
	}
	println(tree.Value)
	loop(tree.Left)
	loop(tree.Right)
}

求树的最大深度

type Node struct{
	Value int
	Childs []*Node
}

func deep(tree *Node) int{
	if tree == nil{
		return 0
	}
	var childMaxDeep int = 0
	for index := range tree.Childs{
		var dp = deep(tree.Childs[index])
		if dp > childMaxDeep{
			childMaxDeep = dp
		}
	}
	return  childMaxDeep + 1
}