Add Python & PHP version

.gitignore

@@ -1,3 +1,4 @@
+# C
 # Prerequisites
 *.d
 
@@ -50,3 +51,149 @@ modules.order
 Module.symvers
 Mkfile.old
 dkms.conf
+
+
+# Python
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+
+# Other
+.vscode/
+data/*.txt

README.md

@@ -0,0 +1,31 @@
+# Pi Search
+
+从 π 的小数点后 **1,000,000,000** 位中搜索指定的数字串位置
+
+ Demo: [快速寻找 8 位生日](https://jasongzy.com/pi-search.php)
+
+## π 的数据来源
+
+使用 [y-cruncher](http://www.numberworld.org/y-cruncher/) 生成了包含 10 亿位十进制数字字符的文本文档 `./data/Pi - Dec - Chudnovsky.txt`（约 950 MB，未包含在仓库内）
+
+为了加快 8 位生日的查询速度，预先遍历了 从 1900-01-01 至 2050-12-31 的所有合法日期，并将它们的位置存入了 SQLite 数据库（`./data/pi.db`）。`date_search_sqlite.py` 和 `pi-search.php` 均调用了此数据库以实现高速查询。
+
+## 查询速度
+
+如果直接遍历匹配原始的 txt 文件，搜索耗时将与目标出现的位置有关，最长约为 1.6 秒。
+
+采用 SQLite 后，8 位生日的查询平均耗时在 1 ms 以下。
+
+## 查询到的概率
+
+从 N 位随机数中发现 d 位连续数字（N >> d）的概率为：
+
+<img src="http://latex.codecogs.com/gif.latex?1-(1-0.1^d)^N" />
+
+因此可以推测，在 π 的前 10 亿位中找到任意 8 位数字的概率约为 99.995%，实测从 1900 年至 2050 年的所有合法 "年月日" 8 位字符串都能从中找到。
+
+## Inspired by
+
+- [The Pi-Search Page](https://www.angio.net/pi/)
+- [Irrational Numbers Search Engine](http://www.subidiom.com/pi/)
+- [北大数院人 微信公众号](https://mp.weixin.qq.com/s?__biz=MzU3NzA0OTA5Mg==&mid=2247492451&idx=1&sn=e14e794bae706d7c2a4f964325d2e404)

create_sqlite.py

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+import datetime
+import sqlite3
+
+from pisearch import get_digits, search_in_Pi
+
+
+def dateRange(start, end, step=1, format=r"%Y%m%d"):
+    strptime, strftime = datetime.datetime.strptime, datetime.datetime.strftime
+    days = (strptime(end, format) - strptime(start, format)).days
+    return [
+        strftime(strptime(start, format) + datetime.timedelta(i), format)
+        for i in range(0, days, step)
+    ]
+
+
+conn = sqlite3.connect(r"data/pi.db")
+c = conn.cursor()
+
+c.execute(
+    """CREATE TABLE BIRTHDAY
+       (DATE      INT PRIMARY KEY,
+        POSITION  INT UNIQUE);"""
+)
+
+date_list = dateRange("19000101", "20510101")
+digits = get_digits(r"data/Pi - Dec - Chudnovsky.txt")
+if digits:
+    for date in date_list:
+        position = search_in_Pi(date, digits)
+        if position:
+            t = (int(date), position)
+            c.execute(
+                "INSERT INTO BIRTHDAY (DATE,POSITION) \
+                 VALUES (?, ?)",
+                t,
+            )
+            print("success: " + date)
+            conn.commit()
+        else:
+            print("Not found: " + date)
+else:
+    print("Pi file error!")
+
+conn.commit()
+conn.close()

date_search.py

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+import sys
+import time
+
+from pisearch import get_digits, search_pi
+
+
+def judge_birthday(number: str):
+    day_in_month = {
+        "01": 31,
+        "02": 28,
+        "03": 31,
+        "04": 30,
+        "05": 31,
+        "06": 30,
+        "07": 31,
+        "08": 31,
+        "09": 30,
+        "10": 31,
+        "11": 30,
+        "12": 31,
+    }
+    if not (number.isdecimal()):
+        return False
+    if len(number) < 8:
+        # number = "19" + number
+        return False
+    year = int(number[:4])
+    month = int(number[4:6])
+    day = int(number[6:])
+    if (year > 2050) or (year < 1900):
+        return False
+    if (month > 12) or (month < 1):
+        return False
+    else:
+        day_correct = day_in_month[number[4:6]]
+        if (year % 400 == 0) or (year % 4 == 0 and year % 100 != 0):
+            day_correct += 1
+        if (day < 1) or (day > day_correct):
+            return False
+    return True
+
+
+if __name__ == "__main__":
+    digits = get_digits(r"data/Pi - Dec - Chudnovsky.txt")
+    if digits:
+        if len(sys.argv) > 1:
+            date = sys.argv[1]
+        else:
+            print("Enter birthday (8 digits): ", end="")
+            date = input()
+        if judge_birthday(date) or True:
+            start_time = time.time()
+            position = search_pi(date, digits)
+            end_time = time.time()
+            print("Query takes %.2f ms" % ((end_time - start_time) * 1000.0))
+            if position:
+                print('position of "%s" : %s' % (date, position))
+            else:
+                print("Not found!")
+        else:
+            print("Invalid birthday!")
+    else:
+        print("Pi file error!")

date_search_sqlite.py

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+import sqlite3
+import sys
+import time
+from date_search import judge_birthday
+
+
+def query_pi(datebase: str, date: int):
+    try:
+        conn = sqlite3.connect(datebase)
+        c = conn.cursor()
+        cursor = c.execute("SELECT POSITION from BIRTHDAY where DATE=?", (date,))
+        result = cursor.fetchone()
+        if not result:
+            return None
+        conn.close()
+        return result[0]
+    except Exception as e:
+        print(e)
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        date = sys.argv[1]
+    else:
+        print("Enter birthday (8 digits): ", end="")
+        date = input()
+    if judge_birthday(date):
+        start_time = time.time()
+        position = query_pi(r"data/pi.db", int(date))
+        end_time = time.time()
+        print("Query takes %.2f ms" % ((end_time - start_time) * 1000.0))
+        print(position)
+    else:
+        print("Invalid birthday!")