Range Sum Query - Immutable

python/leetcode/Range Sum Query - Immutable.py

@@ -0,0 +1,25 @@
+from typing import List
+
+
+class NumArray:
+
+    def __init__(self, nums: List[int]):
+        self.nums = nums
+
+        self.sums = [0]
+        for i in range(0, len(nums)):
+            self.sums.append(nums[i] + self.sums[i])
+
+    def sumRange(self, left: int, right: int) -> int:
+        right = right + 1
+        res = self.sums[right] if left == 0 else self.sums[right] - self.sums[left]
+        return res
+
+
+if __name__ == "__main__":
+    obj = NumArray([-2, 0, 3, -5, 2, -1])
+
+    assert obj.sumRange(0, 2) == 1
+    assert obj.sumRange(2, 5) == -1
+    assert obj.sumRange(0, 5) == -3
+

python/leetcode/Ransom Note.py

@@ -0,0 +1,29 @@
+from collections import Counter
+
+
+class Solution:
+    def canConstruct(self, ransomNote: str, magazine: str) -> bool:
+        r = Counter(ransomNote)
+        m = Counter(magazine)
+
+        for i in ransomNote:
+            if r[i] > m.get(i, 0):
+                return False
+
+        return True
+
+
+if __name__ == "__main__":
+    obj = Solution()
+
+    ransomNote = "a"
+    magazine = "b"
+    assert obj.canConstruct(ransomNote, magazine) is False
+
+    ransomNote = "aa"
+    magazine = "ab"
+    assert obj.canConstruct(ransomNote, magazine) is False
+
+    ransomNote = "aa"
+    magazine = "aab"
+    assert obj.canConstruct(ransomNote, magazine) is True