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在 Perl 和 Go 中探索密码强度和数字验证

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在本文中，我将解决 perl weekly challenge #287 中的两个挑战：加强弱密码和验证数字。我将为这两项任务提供解决方案，展示 perl 和 go 中的实现。

加强弱密码

第一个任务是确定使密码更安全所需的最少更改次数。强密码的标准是：

至少有 6 个字符。
至少包含 1 个小写字母、1 个大写字母和 1 个数字。
不包含三个连续相同的字符。

示例

输入：“a”→输出：5
输入：“ab2”→ 输出：3
输入：“paasw0rd”→输出：0
输入：“paaasw0rd”→输出：1
输入：“aaaaa”→输出：2

解决方案

perl 实现

#!/usr/bin/perl
use strict;
use warnings;
use list::util 'max';

# function to count groups of three or more repeating characters
sub count_repeats {
    my ($str) = @_;
    my $repeats = 0;

    # find repeating characters and count the required changes
    while ($str =~ /(.)\1{2,}/g) {
        $repeats += int(length($&) / 3);
    }

    return $repeats;
}

# function to calculate the minimum steps to create a strong password
sub minimum_steps_to_strong_password {
    my ($str) = @_;
    my $length = length($str);

    # check if the password contains the required character types
    my $has_lower = $str =~ /[a-z]/;
    my $has_upper = $str =~ /[a-z]/;
    my $has_digit = $str =~ /\d/;

    # calculate the number of types needed
    my $types_needed = !$has_lower + !$has_upper + !$has_digit;
    my $repeats = count_repeats($str);

    # return the minimum steps based on the length of the password
    return ($length < 6) ? max(6 - $length, $types_needed) : $types_needed + $repeats;
}

1;

perl 实现的测试

use strict;
use warnings;
use test::more;
require "./ch-1.pl";

my @tests = (
    ["a", 5],
    ["ab2", 3],
    ["paasw0rd", 0],
    ["paaasw0rd", 1],
    ["aaaaa", 2],
);

foreach my $test (@tests) {
    my ($input, $expected) = @$test;
    my $result = minimum_steps_to_strong_password($input);
    is($result, $expected, "input: '$input'");
}

done_testing();

实施

package main

import (
    "regexp"
)

func countrepeats(password string) int {
    repeats := 0
    count := 1

    for i := 1; i < len(password); i++ {
        if password[i] == password[i-1] {
            count++
        } else {
            repeats += count / 3
            count = 1
        }
    }
    repeats += count / 3
    return repeats
}

func minimumstepstostrongpassword(password string) int {
    length := len(password)

    // use regex to check for character types
    haslower := regexp.mustcompile(`[a-z]`).matchstring(password)
    hasupper := regexp.mustcompile(`[a-z]`).matchstring(password)
    hasdigit := regexp.mustcompile(`\d`).matchstring(password)

    // calculate the number of types needed
    typesneeded := booltoint(!haslower) + booltoint(!hasupper) + booltoint(!hasdigit)

    repeats := countrepeats(password)

    // return the minimum steps based on the length of the password
    if length < 6 {
        return max(6-length, typesneeded)
    }
    return typesneeded + repeats
}


func booltoint(b bool) int {
    if b {
        return 1
    }
    return 0
}

func max(a, b int) int {
    if a > b {
        return a
    }
    return b
}

go 实现的测试

package main

import (
    "testing"
)

func testminimumstepstostrongpassword(t *testing.t) {
    tests := []struct {
        password string
        expected int
    }{
        {"a", 5},
        {"ab2", 3},
        {"paasw0rd", 0},
        {"paaasw0rd", 1},
        {"aaaaa", 2},
    }

    for _, test := range tests {
        result := minimumstepstostrongpassword(test.password)
        if result != test.expected {
            t.errorf("for password '%s', expected %d but got %d", test.password, test.expected, result)
        }
    }
}

验证数字

第二个任务涉及验证数字。目标是确定给定的字符串是否代表有效的数字。有效号码的标准是：

一个整数（可选后跟指数表示法）。
十进制数（可选后跟指数表示法）。
整数可以选择带有符号（- 或 +），后跟数字。

示例

输入：“1”→输出：true
输入：“a”→输出：false
输入：“。” → 输出：假
输入：“1.2e4.2”→输出：false
输入：“-1”。 → 输出：真
输入：“+1e-8”→ 输出：true
输入：“.44”→ 输出：true

解决方案

perl 实现

#!/usr/bin/perl
use strict;
use warnings;

sub is_valid_number {
    my ($str) = @_;

    # regex for valid numbers
    my $regex = qr{
        ^            # start of the string
        [+-]?        # optional sign
        (?:          # start of the number group
            \d+      # integer: at least one digit
            (?:      # start of the optional decimal part
                \.   # decimal point
                \d*  # followed by zero or more digits
            )?       # group is optional
            |        # or
            \.       # just a decimal point
            \d+      # followed by one or more digits
        )            # end of the number group
        (?:          # start of the optional exponent group
            [ee]     # 'e' or 'e'
            [+-]?    # optional sign
            \d+      # followed by one or more digits
        )?           # exponent is optional
        $            # end of the string
    }x;

    # return 1 for valid, 0 for invalid
    return $str =~ $regex ? 1 : 0;
}

1;

perl 实现的测试

#!/usr/bin/perl
use strict;
use warnings;
use test::more;

require './ch-2.pl';

# define test cases
my @test_cases = (
    ["1", 1, 'valid integer'],
    ["a", 0, 'invalid input'],
    [".", 0, 'single dot'],
    ["1.2e4.2", 0, 'invalid exponent'],
    ["-1.", 1, 'valid decimal'],
    ["+1e-8", 1, 'valid scientific notation'],
    [".44", 1, 'valid decimal starting with dot'],
);

# loop through test cases and run tests
foreach my $case (@test_cases) {
    my $result = is_valid_number($case->[0]);
    is($result, $case->[1], $case->[2]);
}

done_testing();

实施

package main

import (
    "regexp"
)

// isvalidnumber checks if the given string is a valid number.
func isvalidnumber(str string) bool {
    regex := `^[+-]?((\d+(\.\d*)?)|(\.\d+))([ee][+-]?\d+)?$`
    matched, _ := regexp.matchstring(regex, str)
    return matched
}

go 实现的测试

package main

import (
    "testing"
)

func TestIsValidNumber(t *testing.T) {
    testCases := []struct {
        input    string
        expected bool
    }{
        {"1", true},
        {"a", false},
        {".", false},
        {"1.2e4.2", false},
        {"-1.", true},
        {"+1E-8", true},
        {".44", true},
    }

    for _, tc := range testCases {
        result := isValidNumber(tc.input)
        if result != tc.expected {
            t.Errorf("isValidNumber(%q) = %v; expected %v", tc.input, result, tc.expected)
        }
    }
}