Added W10 materials

README.md

@@ -48,8 +48,8 @@
 | 07     | DFS & BFS              | [Slides][Slides_W07] | [Test][WarmUp_test_W07] | [Contest][ContestID_W07] | 25.11.2024 19:00 UTC+3 |
 | 08     | Shortest paths         | [Slides][Slides_W08] | [Test][WarmUp_test_W08] | [Contest][ContestID_W08] | 02.12.2024 19:00 UTC+3 |
 | 09     | RSQ & RMQ              | [Slides][Slides_W09] | [Test][WarmUp_test_W09] | [Contest][ContestID_W09] | 09.12.2024 19:00 UTC+3 |
+| 10     | Hashing                | [Slides][Slides_W10] | [Test][WarmUp_test_W10] | [Contest][ContestID_W10] | 16.12.2024 19:00 UTC+3 |
 <!---
-| 10     | Hashing                | [Slides][Slides_W10] | [Test][WarmUp_test_W10] | [Contest][ContestID_W10] | ??.12.2024 19:00 UTC+3 |
 | 11     | Binary Search Tree     | [Slides][Slides_W11] | None                    | None                     | None                   |
 --->
 

week10_hashing/rabin_karp.py

@@ -0,0 +1,34 @@
+from random import randint
+
+
+def c_to_i(ch):
+    return ord(ch) - ord('a') + 1
+
+
+p = 10**9 + 7
+a = randint(c_to_i('z') + 1, p - 1)
+
+
+def find_substrings_rabin_karp(s, t):
+    h = [0] * (len(s) + 1)
+    a_pow = [1] * (len(s) + 1)
+    for i in range(len(s)):
+        h[i + 1] = (h[i] + c_to_i(s[i]) * a_pow[i]) % p
+        a_pow[i + 1] = (a_pow[i] * a) % p
+
+    h_t = 0
+    for i in range(len(t)):
+        h_t = (h_t + c_to_i(t[i]) * a_pow[i]) % p
+
+    substrings = []
+    for i in range(len(s) - len(t) + 1):
+        if (h_t * a_pow[i]) % p == (h[i + len(t)] - h[i]) % p:
+            if all([s[i + j] == t[j] for j in range(len(t))]):
+                substrings.append(i)
+    return substrings
+
+
+if __name__ == '__main__':
+    s = input().strip()
+    t = input().strip()
+    print(' '.join(map(str, find_substrings_rabin_karp(s, t))))