最长公共前缀

package main

import (
    "fmt"
    "strings"
)

func main() {
    fmt.Printf("%+v\n",longestCommonPrefix([]string{"dog","racecar","car"}))
}

func longestCommonPrefix(strs []string) string {
    if len(strs) <= 0 {
        return ""
    }
    index := 0
    result := strings.Builder{}
    for {
        letter := ""
        for _, str := range strs {
            if len(str) <= index {
                letter = ""
                break
            }
            if len(letter) <= 0 {
                letter = str[index : index+1]
                continue
            }
            if str[index:index+1] != letter {
                letter = ""
                break
            }
        }
        index ++
        if len(letter) <= 0 {
            break
        }
        result.WriteString(letter)
    }
    return result.String()
}