题解 | #字符串加解密#

package main

import (
    "fmt"
)

func encode(s string) string {
    size := len(s)
    sb := []byte(s)

    for i:=0; i<size; i++ {
        ch := s[i]
        if 'a' <= s[i] && s[i] <= 'z' {
            if s[i] == 'z' {
                ch = 'A'
            } else {
                ch = s[i] + 1 - 32
            }
        }
        if 'A' <= s[i] && s[i] <= 'Z' {
            if s[i] == 'Z' {
                ch = 'a'
            } else {
                ch = s[i] + 1 + 32
            }
        }
        if '0' <= s[i] && s[i] <= '9' {
            if s[i] == '9' {
                ch = '0'
            } else {
                ch = s[i] + 1
            }
        }
        sb[i] = ch
    }

    return string(sb)
}

func decode(s string) string {
    size := len(s)
    sb := []byte(s)

    for i:=0; i<size; i++ {
        ch := s[i]
        if 'a' <= s[i] && s[i] <= 'z' {
            if s[i] == 'a' {
                ch = 'Z'
            } else {
                ch = s[i] - 32 - 1
            }
        }
        if 'A' <= s[i] && s[i] <= 'Z' {
            if s[i] == 'A' {
                ch = 'z'
            } else {
                ch = s[i] -1 + 32
            }
        }
        if '0' <= s[i] && s[i] <= '9' {
            if s[i] == '0' {
                ch = '9'
            } else {
                ch = s[i] - 1
            }
        }
        sb[i] = ch
    }

    return string(sb)
}

func main() {
    var encodePassword string
    var decodePassword string

    fmt.Scan(&encodePassword, &decodePassword)

    fmt.Println(encode(encodePassword))
    fmt.Println(decode(decodePassword))
}

// 保证输入的字符串都是只由大小写字母或者数字组成
// 本题输入为一行两个字符串，中间空空格分开，所以采用：fmt.Scan(&encodePassword, &decodePassword)