{"id":3526,"date":"2025-10-20T20:03:27","date_gmt":"2025-10-20T12:03:27","guid":{"rendered":"https:\/\/tobykskgd.life\/?p=3526"},"modified":"2025-10-20T20:03:29","modified_gmt":"2025-10-20T12:03:29","slug":"cs50p-problem-set-1","status":"publish","type":"post","link":"https:\/\/tobykskgd.life\/index.php\/cs50p-problem-set-1\/","title":{"rendered":"CS50P Problem Set 1"},"content":{"rendered":"\n

\u8bfe\u7a0b\uff1aCS50\u2019s Introduction to Programming with Python<\/a><\/p>\n\n\n\n

CS50 Python 2025 \u8bfe\u7a0b\u7684\u95ee\u9898\u96c6\u4f5c\u4e1a\u63d0\u4ea4\u3002\u4e3b\u8981\u63d0\u4f9b\u4e00\u4e2a\u672c\u4eba\u7684\u89e3\u9898\u601d\u8def\uff0c\u4ec5\u4f9b\u53c2\u8003\u3002<\/p>\n\n\n\n

Deep Thought<\/h3>\n\n\n\n

Problem:<\/p>\n\n\n\n

\n

\u201cAll right,\u201d said the computer, and settled into silence again. The two men fidgeted. The tension was unbearable.\u201c\u597d\u5427\uff0c\u201d\u7535\u8111\u8bf4\uff0c\u7136\u540e\u53c8\u9677\u5165\u4e86\u6c89\u9ed8\u3002\u4e24\u4e2a\u4eba\u5750\u7acb\u4e0d\u5b89\u3002\u7d27\u5f20\u611f\u96be\u4ee5\u5fcd\u53d7\u3002
\u201cYou\u2019re really not going to like it,\u201d observed Deep Thought.\u201c\u4f60\u771f\u7684\u4e0d\u4f1a\u559c\u6b22\u5b83\uff0c\u201d\u6df1\u601d\u719f\u8651\u8bf4\u3002
\u201cTell us!\u201d  \u201c\u544a\u8bc9\u6211\u4eec\uff01\u201d
\u201cAll right,\u201d said Deep Thought. \u201cThe Answer to the Great Question\u2026\u201d\u201c\u597d\u5427\uff0c\u201d\u6df1\u601d\u8bf4\u3002\u201c\u8fd9\u4e2a\u4f1f\u5927\u95ee\u9898\u7684\u7b54\u6848……\u201d
\u201cYes\u2026!\u201d  \u201c\u662f\u7684……\uff01\u201d
\u201cOf Life, the Universe and Everything\u2026\u201d said Deep Thought.\u201c\u5173\u4e8e\u751f\u547d\u3001\u5b87\u5b99\u548c\u4e00\u5207……\u201d\u6df1\u601d\u8bf4\u9053\u3002
\u201cYes\u2026!\u201d  \u201c\u662f\u7684……\uff01\u201d
\u201cIs\u2026\u201d said Deep Thought, and paused.\u201c\u662f……\u201d\u6df1\u601d\u8bf4\u9053\uff0c\u505c\u987f\u4e86\u4e00\u4e0b\u3002
\u201cYes\u2026!\u201d  \u201c\u662f\u7684……\uff01\u201d
\u201cIs\u2026\u201d  \u201c\u662f……\u201d
\u201cYes\u2026!!!\u2026?\u201d  \u201c\u662f\u7684……!! \u2026?\u201d
\u201cForty-two,\u201d said Deep Thought, with infinite majesty and calm.\u201d\u201c\u56db\u5341\u4e8c\uff0c\u201d\u6df1\u601d\u8bf4\uff0c\u5e26\u7740\u65e0\u9650\u7684\u5a01\u4e25\u548c\u5e73\u9759\u3002<\/p>\n\n\n\n

\u2014 The Hitchhiker\u2019s Guide to the Galaxy<\/em>, Douglas Adams\u2014 \u94f6\u6cb3\u7cfb\u6f2b\u6e38\u6307\u5357 <\/em>\uff0c\u9053\u683c\u62c9\u65af\u00b7\u4e9a\u5f53\u65af<\/p>\n<\/blockquote>\n\n\n\n

In deep.py<\/code>, implement a program that prompts the user for the answer to the Great Question of Life, the Universe and Everything, outputting Yes<\/code> if the user inputs 42<\/code> or (case-insensitively) forty-two<\/code> or forty two<\/code>. Otherwise output No<\/code>.
deep.py<\/code>\uff0c\u5b9e\u73b0\u4e00\u4e2a\u7a0b\u5e8f\uff0c\u63d0\u793a\u7528\u6237\u56de\u7b54\u751f\u547d\u3001\u5b87\u5b99\u548c\u4e07\u7269\u7684\u4f1f\u5927\u95ee\u9898\uff0c\u5982\u679c\u7528\u6237\u8f93\u5165 42<\/code> \u6216\uff08\u4e0d\u533a\u5206\u5927\u5c0f\u5199\uff09 \u56db\u5341\u4e8c<\/code>\u6216\u56db\u5341\u4e8c <\/code>\uff0c\u5219\u8f93\u51fa Yes<\/code>\u3002\u5426\u5219\u8f93\u51fa No<\/code>\u3002<\/p>\n\n\n\n

Submit:<\/p>\n\n\n\n

answer = input(\"What is the Answer to the Great Question of Life, the Universe, and Everything? \")\n\nif answer.replace(\" \", \"\") == \"42\" or answer.lower() == \"forty-two\" or answer.lower() == \"forty two\":\n    print(\"Yes\")\nelse:\n    print(\"No\")\n<\/code><\/pre>\n\n\n\n
Home Federal Savings Bank<\/h3>\n\n\n\n
Problem:<\/p>\n\n\n\n
In season 7, episode 24<\/a> of Seinfeld<\/a>, Kramer<\/a> visits a bank that promises to give $100 to anyone who isn\u2019t greeted with a \u201chello.\u201d Kramer is instead greeted with a \u201chey,\u201d which he insists isn\u2019t a \u201chello,\u201d and so he asks for $100. The bank\u2019s manager proposes a compromise: \u201cYou got a greeting that starts with an \u2018h,\u2019 how does $20 sound?\u201d Kramer accepts.
\u5728\u300a \u5b8b\u98de\u6b63\u4f20 <\/a>\u300b \u7b2c 7 \u5b63\u7b2c 24 \u96c6\u4e2d <\/a>\uff0c \u514b\u83b1\u9ed8<\/a>\u62dc\u8bbf\u4e86\u4e00\u5bb6\u94f6\u884c\uff0c\u8be5\u94f6\u884c\u627f\u8bfa\u5411\u4efb\u4f55\u6ca1\u6709\u6253\u62db\u547c\u201c\u4f60\u597d\u201d\u7684\u4eba\u63d0\u4f9b 100 \u7f8e\u5143\u3002\u76f8\u53cd\uff0c\u514b\u83b1\u9ed8\u53d7\u5230\u4e86\u201c\u563f\u201d\u7684\u6b22\u8fce\uff0c\u4ed6\u575a\u79f0\u8fd9\u4e0d\u662f\u201c\u4f60\u597d\u201d\uff0c\u6240\u4ee5\u4ed6\u8981\u4e86 100 \u7f8e\u5143\u3002\u94f6\u884c\u7ecf\u7406\u63d0\u51fa\u4e86\u4e00\u4e2a\u6298\u8877\u65b9\u6848\uff1a\u201c\u4f60\u6709\u4e00\u4e2a\u4ee5’h’\u5f00\u5934\u7684\u95ee\u5019\u8bed\uff0c20 \u7f8e\u5143\u542c\u8d77\u6765\u600e\u4e48\u6837\uff1f\u514b\u83b1\u9ed8\u63a5\u53d7\u4e86\u3002<\/p>\n\n\n\n
In a file called bank.py<\/code>, implement a program that prompts the user for a greeting. If the greeting starts with \u201chello\u201d, output $0<\/code>. If the greeting starts with an \u201ch\u201d (but not \u201chello\u201d), output $20<\/code>. Otherwise, output $100<\/code>. Ignore any leading whitespace in the user\u2019s greeting, and treat the user\u2019s greeting case-insensitively.
\u5728\u540d\u4e3a bank.py<\/code> \u7684\u6587\u4ef6\u4e2d\uff0c\u5b9e\u73b0\u4e00\u4e2a\u63d0\u793a\u7528\u6237\u6253\u95ee\u5019\u8bed\u7684\u7a0b\u5e8f\u3002\u5982\u679c\u95ee\u5019\u8bed\u4ee5\u201chello\u201d\u5f00\u5934\uff0c\u5219\u8f93\u51fa $0<\/code>\u3002\u5982\u679c\u95ee\u5019\u8bed\u4ee5\u201ch\u201d\u5f00\u5934\uff08\u4f46\u4e0d\u662f\u201chello\u201d\uff09\uff0c\u5219\u8f93\u51fa $20<\/code>\u3002\u5426\u5219\uff0c\u8f93\u51fa 100 \u7f8e\u5143 <\/code>\u3002\u5ffd\u7565\u7528\u6237\u95ee\u5019\u8bed\u4e2d\u7684\u4efb\u4f55\u524d\u5bfc\u7a7a\u683c\uff0c\u5e76\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u6765\u5904\u7406\u7528\u6237\u7684\u95ee\u5019\u8bed\u3002<\/p>\n\n\n\n
Submit:<\/p>\n\n\n\n
say = input(\"Greeting: \")\n\nif say.lower().strip()[:5] == \"hello\":\n    print(\"$0\")\nelif say.lower().strip()[:1] == \"h\":\n    print(\"$20\")\nelse:\n    print(\"$100\")\n<\/code><\/pre>\n\n\n\n
File Extensions<\/h3>\n\n\n\n
Problem:<\/p>\n\n\n\n
Even though Windows and macOS sometimes hide them, most files have file extensions<\/a>, a suffix that starts with a period (.<\/code>) at the end of their name. For instance, file names for GIFs<\/a> end with .gif<\/code>, and file names for JPEGs<\/a> end with .jpg<\/code> or .jpeg<\/code>. When you double-click on a file to open it, your computer uses its file extension to determine which program to launch.
\u5c3d\u7ba1 Windows \u548c macOS \u6709\u65f6\u4f1a\u9690\u85cf\u5b83\u4eec\uff0c\u4f46\u5927\u591a\u6570\u6587\u4ef6\u90fd\u6709\u6587\u4ef6\u6269\u5c55\u540d <\/a>\uff0c\u5373\u540d\u79f0\u672b\u5c3e\u4ee5\u53e5\u70b9 \uff08.\uff09<\/code> \u5f00\u5934\u7684\u540e\u7f00\u3002\u4f8b\u5982\uff0cGIF<\/a> \u7684\u6587\u4ef6\u540d\u4ee5 .gif<\/code> \u7ed3\u5c3e\uff0cJPEG<\/a> \u7684\u6587\u4ef6\u540d\u4ee5 .jpg<\/code> \u6216 .jpeg<\/code> \u7ed3\u5c3e\u3002\u5f53\u60a8\u53cc\u51fb\u6587\u4ef6\u4ee5\u6253\u5f00\u5b83\u65f6\uff0c\u60a8\u7684\u8ba1\u7b97\u673a\u4f1a\u4f7f\u7528\u5176\u6587\u4ef6\u6269\u5c55\u540d\u6765\u786e\u5b9a\u8981\u542f\u52a8\u7684\u7a0b\u5e8f\u3002<\/p>\n\n\n\n
Web browsers, by contrast, rely on media types<\/a>, formerly known as MIME types, to determine how to display files that live on the web. When you download a file from a web server, that server sends an HTTP header<\/a>, along with the file itself, indicating the file\u2019s media type. For instance, the media type for a GIF is image\/gif<\/code>, and the media type for a JPEG is image\/jpeg<\/code>. To determine the media type for a file, a web server typically looks at the file\u2019s extension, mapping one to the other.
\u76f8\u6bd4\u4e4b\u4e0b\uff0cWeb \u6d4f\u89c8\u5668\u4f9d\u8d56\u4e8e\u5a92\u4f53\u7c7b\u578b <\/a>\uff08\u4ee5\u524d\u79f0\u4e3a MIME \u7c7b\u578b\uff09\u6765\u786e\u5b9a\u5982\u4f55\u663e\u793a Web \u4e0a\u7684\u6587\u4ef6\u3002\u5f53\u60a8\u4ece Web \u670d\u52a1\u5668\u4e0b\u8f7d\u6587\u4ef6\u65f6\uff0c\u8be5\u670d\u52a1\u5668\u4f1a\u53d1\u9001\u4e00\u4e2a HTTP \u6807\u5934<\/a>\u4ee5\u53ca\u6587\u4ef6\u672c\u8eab\uff0c\u6307\u793a\u6587\u4ef6\u7684\u5a92\u4f53\u7c7b\u578b\u3002\u4f8b\u5982\uff0cGIF \u7684\u5a92\u4f53\u7c7b\u578b\u662f image\/gif\uff0cJPEG<\/code> \u7684\u5a92\u4f53\u7c7b\u578b\u662f image\/jpeg<\/code>\u3002\u4e3a\u4e86\u786e\u5b9a\u6587\u4ef6\u7684\u5a92\u4f53\u7c7b\u578b\uff0cWeb \u670d\u52a1\u5668\u901a\u5e38\u4f1a\u67e5\u770b\u6587\u4ef6\u7684\u6269\u5c55\u540d\uff0c\u5c06\u4e00\u4e2a\u6269\u5c55\u540d\u6620\u5c04\u5230\u53e6\u4e00\u4e2a\u6269\u5c55\u540d\u3002<\/p>\n\n\n\n
See developer.mozilla.org\/en-US\/docs\/Web\/HTTP\/Basics_of_HTTP\/MIME_types\/Common_types<\/a> for common types.
\u5e38\u89c1\u7c7b\u578b\u8bf7\u53c2\u89c1 developer.mozilla.org\/en-US\/docs\/Web\/HTTP\/Basics_of_HTTP\/MIME_types\/Common_types<\/a>\u3002<\/p>\n\n\n\n
In a file called extensions.py<\/code>, implement a program that prompts the user for the name of a file and then outputs that file\u2019s media type if the file\u2019s name ends, case-insensitively, in any of these suffixes:
\u5728\u540d\u4e3a extensions.py<\/code> \u7684\u6587\u4ef6\u4e2d\uff0c\u5b9e\u73b0\u4e00\u4e2a\u7a0b\u5e8f\uff0c\u8be5\u7a0b\u5e8f\u63d0\u793a\u7528\u6237\u8f93\u5165\u6587\u4ef6\u540d\uff0c\u7136\u540e\u5728\u6587\u4ef6\u540d\u4ee5\u4ee5\u4e0b\u4efb\u4f55\u540e\u7f00\u7ed3\u5c3e\u65f6\u8f93\u51fa\u8be5\u6587\u4ef6\u7684\u5a92\u4f53\u7c7b\u578b\uff0c\u4e0d\u533a\u5206\u5927\u5c0f\u5199\uff1a<\/p>\n\n\n\n