Severity: 8192
Message: Creation of dynamic property CI_Cache::$apc is deprecated
Filename: libraries/Driver.php
Line Number: 188
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Cacher.php
Line: 22
Function: driver
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Cacher.php
Line: 17
Function: initiateCache
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 12
Function: __construct
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: Creation of dynamic property CI_Cache::$file is deprecated
Filename: libraries/Driver.php
Line Number: 188
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Cacher.php
Line: 22
Function: driver
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Cacher.php
Line: 17
Function: initiateCache
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 12
Function: __construct
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: Creation of dynamic property Contents_model::$best_cnt is deprecated
Filename: ver3/Contents_model.php
Line Number: 17
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/models/ver3/Contents_model.php
Line: 17
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 440
Function: model
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 29
Function: initMenu
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 12
Function: __construct
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: Creation of dynamic property Contents_model::$popular_cnt is deprecated
Filename: ver3/Contents_model.php
Line Number: 18
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/models/ver3/Contents_model.php
Line: 18
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 440
Function: model
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 29
Function: initMenu
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 12
Function: __construct
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: Creation of dynamic property Article_model::$best_cnt is deprecated
Filename: ver3/Article_model.php
Line Number: 18
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/models/ver3/Article_model.php
Line: 18
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 13
Function: model
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: Creation of dynamic property Article_model::$popular_cnt is deprecated
Filename: ver3/Article_model.php
Line Number: 19
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/models/ver3/Article_model.php
Line: 19
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 13
Function: model
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: urldecode(): Passing null to parameter #1 ($string) of type string is deprecated
Filename: ver3/Member_model.php
Line Number: 279
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/models/ver3/Member_model.php
Line: 279
Function: urldecode
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 123
Function: getMemberView
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: ver3/Article.php
Line Number: 124
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 124
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: Warning
Message: Trying to access array offset on value of type null
Filename: ver3/Article.php
Line Number: 125
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 125
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: Warning
Message: mkdir(): Permission denied
Filename: libraries/Common.php
Line Number: 202
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 202
Function: mkdir
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 236
Function: getLatexImg
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 249
Function: parseLatexImg
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 131
Function: initBoardView
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: Warning
Message: file_put_contents(/DATA/upload/polymath/latex/202f51921287058aab9d4014a0acf94c.gif): Failed to open stream: No such file or directory
Filename: libraries/Common.php
Line Number: 213
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 213
Function: file_put_contents
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Common.php
Line: 236
Function: getLatexImg
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 249
Function: parseLatexImg
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 131
Function: initBoardView
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: 8192
Message: Creation of dynamic property CI_Cache::$dummy is deprecated
Filename: libraries/Driver.php
Line Number: 188
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/models/ver3/Article_model.php
Line: 674
Function: get
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 266
Function: getComment
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 131
Function: initBoardView
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
수학동아 독자 중 이번에 중학교로 올라가는 학생들이 많을 것입니다. 이 때가 학생들이 빠르게 변하는 만큼 초등학교때와는 다르게 나쁜 일들을 좀 하는 학생들이 생기죠. 남의 사물함을 뒤져서 도둑질 하는 학생들도 자주 보입니다. 그러면 여러분은 자물쇠가 아마도 필요하실텐데요, 어떤 자물쇠가 좋을까요? 어떤 자물쇠가 좋을지 알아보기 위해 자물쇠의 종류 별로 살펴봅시다.
1.돌리는 자물쇠
사진출처: (주)자커
돌리는 자물쇠는 각 자리별로 10가지 경우의 수가 있기 때문에 세자릿수인 경우는 103=1000가지, 네자릿수인 경우는 104=10000가지가 나옵니다.
2.누르는 자물쇠
사진출처: (주)자커
누르는 자물쇠는 각 버튼마다 2가지 경우가 있으므로 8버튼인 경우에는 28=256가지, 10버튼인 경우에는 210=1024가지가 있습니다.
이렇게까지만 보시면 '돌리는 4자리'>'누르는 10버튼'>'돌리는 3자리'>'누르는 8자리' 순으로 좋다고 할 수 있습니다.
하지만 경우의 수가 아닌 따는데 걸리는 시간이 오래 걸려야 좋은 자물쇠라고 할 수 있습니다.
돌리는 4자리인 경우, 한 칸 돌리는데 1초, 확인하는데 1초 걸린다고 가정하면 전체 경우 중 일의자리가 '9'가 아닌 나머지 90%는 돌리는데 1초, 확인하는데에 1초가 소모되고, 10n의자리가 '9'이고 10n+1의자리가 '9'가 아닌 경우는 전체의
%를 차지하고, 각각 돌리는 데에 n+1초, 확인하는데에 1초가 걸리므로 총 소요시간은 2*9000+3*900+4*90+5*9=21105초가 걸립니다.
돌리는 3자리인 경우, 마찬가지로 계산을 하면 2*900+3*90+4*9=2106초가 걸립니다.
누르는 10자리의 경우에는 '1','2','3'이 눌러져 있고, 나머지 한 개로 나머지 수들을 누를 테니, 초기에 '1','2','3',4'을 누를 4초+일반적인 경우, 한 번 바꾸고 확인하는데 3초, 나머지는 n이상 의 수들이 모두 눌려져 있고, n-1이 눌러져 있지 않다면, 14-n초가 걸리므로 총 소요시간은 7C1*6+(8C2-7C1)*5+(9C3-8C2)*4+(10C4-9C3)*3=7*6+21*5+56*4+210*3=1001초입니다.
위 결과로 보면 돌리는 4자릿수가 10~20배 효과적임을 알 수 있습니다. 다른 종류에 비하여 2배정도 비싼것을 감안하여도 5~10배 더 좋은 자물쇠라고 할 수 있습니다.
*자물쇠를 따는 더 빠른 방법을 알고 계신분은 댓글로 소개해주세요!*
Severity: Warning
Message: Undefined variable $tag_news_list
Filename: inc/article_view.php
Line Number: 90
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/views/ver3/inc/article_view.php
Line: 90
Function: _error_handler
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 221
Function: view
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once
Severity: Warning
Message: Cannot modify header information - headers already sent by (output started at /volume1/web/PhpstormProjects/www_polymath_co_kr/system/core/Exceptions.php:271)
Filename: core/Common.php
Line Number: 570
Backtrace:
Type: TypeError
Message: count(): Argument #1 ($value) must be of type Countable|array, null given
Filename: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/views/ver3/inc/article_view.php
Line Number: 90
Backtrace:
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Article.php
Line: 221
Function: view
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/index.php
Line: 315
Function: require_once