solved(python): baekjoon 2042

Author: himitery

baekjoon/python/2042/__init__.py

@@ -0,0 +1,59 @@
+import sys
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.n, self.m, self.k = map(int, read().split())
+        self.nums = [int(read()) for _ in range(self.n)]
+        self.query = [list(map(int, read().split())) for _ in range(self.m + self.k)]
+
+        self.size, self.tree = self.make_tree()
+
+    def solve(self) -> None:
+        for command, src, dest in self.query:
+            if command == 1:
+                self.update(src - 1, dest)
+            if command == 2:
+                print(self.find_sum(src - 1, dest - 1))
+
+    def make_tree(self) -> tuple[int, list[int]]:
+        size = 1
+        while size < self.n:
+            size <<= 1
+
+        tree = [0 for _ in range(size * 2)]
+        for idx in range(self.n):
+            tree[size + idx] = self.nums[idx]
+        for idx in range(size - 1, 0, -1):
+            tree[idx] = tree[idx * 2] + tree[idx * 2 + 1]
+
+        return size, tree
+
+    def update(self, index: int, num: int) -> None:
+        idx = self.size + index
+        self.tree[idx] = num
+
+        while idx > 1:
+            idx //= 2
+            self.tree[idx] = self.tree[idx * 2] + self.tree[idx * 2 + 1]
+
+    def find_sum(self, src: int, dest: int) -> int:
+        left, right, value = self.size + src, self.size + dest, 0
+
+        while left <= right:
+            if left % 2 == 1:
+                value += self.tree[left]
+                left += 1
+            if right % 2 == 0:
+                value += self.tree[right]
+                right -= 1
+
+            left, right = left // 2, right // 2
+
+        return value
+
+
+if __name__ == "__main__":
+    Problem().solve()

baekjoon/python/2042/main.py

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+[
+  {
+    "input": [
+      "5 2 2",
+      "1",
+      "2",
+      "3",
+      "4",
+      "5",
+      "1 3 6",
+      "2 2 5",
+      "1 5 2",
+      "2 3 5"
+    ],
+    "expected": [
+      "17",
+      "12"
+    ]
+  }
+]

baekjoon/python/2042/sample.json

@@ -0,0 +1,36 @@
+import json
+import os.path
+import unittest
+from io import StringIO
+from unittest.mock import patch
+
+from parameterized import parameterized
+
+from main import Problem
+
+
+def load_sample(filename: str):
+    path = os.path.join(os.path.dirname(os.path.abspath(__file__)), filename)
+
+    with open(path, "r") as file:
+        return [(case["input"], case["expected"]) for case in json.load(file)]
+
+
+class TestCase(unittest.TestCase):
+    @parameterized.expand(load_sample("sample.json"))
+    def test_case(self, case: str, expected: list[str]):
+        # When
+        with (
+            patch("sys.stdin.readline", side_effect=case),
+            patch("sys.stdout", new_callable=StringIO) as output,
+        ):
+            Problem().solve()
+
+            result = output.getvalue().rstrip()
+
+        # Then
+        self.assertEqual("\n".join(expected), result)
+
+
+if __name__ == "__main__":
+    unittest.main()