docs: add Japanese translate documents (#1812)

* docs: add Japanese documents (`ja/docs`)

* docs: add Japanese documents (`ja/codes`)

* docs: add Japanese documents

* Remove pythontutor blocks in ja/

* Add an empty at the end of each markdown file.

* Add the missing figures (use the English version temporarily).

* Add index.md for Japanese version.

* Add index.html for Japanese version.

* Add missing index.assets

* Fix backtracking_algorithm.md for Japanese version.

* Add avatar_eltociear.jpg. Fix image links on the Japanese landing page.

* Add the Japanese banner.

---------

Co-authored-by: krahets <krahets@163.com>

ja/codes/python/chapter_hashing/simple_hash.py

@@ -0,0 +1,58 @@
+"""
+File: simple_hash.py
+Created Time: 2023-06-15
+Author: krahets (krahets@163.com)
+"""
+
+
+def add_hash(key: str) -> int:
+    """加法ハッシュ"""
+    hash = 0
+    modulus = 1000000007
+    for c in key:
+        hash += ord(c)
+    return hash % modulus
+
+
+def mul_hash(key: str) -> int:
+    """乗法ハッシュ"""
+    hash = 0
+    modulus = 1000000007
+    for c in key:
+        hash = 31 * hash + ord(c)
+    return hash % modulus
+
+
+def xor_hash(key: str) -> int:
+    """XORハッシュ"""
+    hash = 0
+    modulus = 1000000007
+    for c in key:
+        hash ^= ord(c)
+    return hash % modulus
+
+
+def rot_hash(key: str) -> int:
+    """回転ハッシュ"""
+    hash = 0
+    modulus = 1000000007
+    for c in key:
+        hash = (hash << 4) ^ (hash >> 28) ^ ord(c)
+    return hash % modulus
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    key = "Hello algorithm"
+
+    hash = add_hash(key)
+    print(f"加法ハッシュ値は {hash}")
+
+    hash = mul_hash(key)
+    print(f"乗法ハッシュ値は {hash}")
+
+    hash = xor_hash(key)
+    print(f"XORハッシュ値は {hash}")
+
+    hash = rot_hash(key)
+    print(f"回転ハッシュ値は {hash}")