[算法]简易字符串压缩PowerShell版

这可能是一个小面试题，给定字符串abbcccdeeet，包含了连续的字符，要求将字符串压缩成a1b2c3d1e3t1。

函数实现

function Compress-String([string]$string)
{
    # argument validation
    if($string.Length -eq 0)
    {
        return [string]::Empty
    }

    # temp character   
    $ch = $string[0]

    # the count of current character
    $count = 1

    # current index
    $i=0

    # string to append result
    $result = New-Object System.Text.StringBuilder
     while($i -lt $string.Length)
     {
        $count = 0

        # loop until find different character
        while($string[$i] -eq $ch)
        {
            $count ++
            $i++
        }

        # append result 
        $result.AppendFormat("{0}{1}",$ch, $count) | Out-Null

        # swap temperary character
        $ch=$string[$i]
     }

     return $result.ToString()
}

测试用例

# test case 1
Compress-String $null
# test case 2
Compress-String ''
# test case 3
Compress-String -string 'abc'
# test case 4
Compress-String -string 'abbcccdeeet'

输出