fix:第三天

14_刷题/day03/problem_solving_18_01.py

+"""
+区域和检索 - 数组不可变
+"""
+from typing import List
+
+
+class NumArray:
+
+    def __init__(self, nums: List[int]):
+        self.nums = nums
+
+    def sumRange(self, left: int, right: int) -> int:
+        """
+        切片  求和
+        :param left:
+        :param right:
+        :return:
+        """
+        return sum(self.nums[left: right + 1])
+
+
+# Your NumArray object will be instantiated and called as such:
+# obj = NumArray(nums)
+# param_1 = obj.sumRange(left,right)
+if __name__ == '__main__':
+    result = NumArray([-2, 0, 3, -5, 2, -1]).sumRange(0, 2)
+    print(result)

14_刷题/day03/problem_solving_18_02.py

+"""
+区域和检索 - 数组不可变
+"""
+from typing import List
+
+
+class NumArray:
+
+    def __init__(self, nums: List[int]):
+        self.nums = nums
+        for i in range(1, len(nums)):
+            # 前缀和
+            self.nums[i] += self.nums[i - 1]
+
+    def sumRange(self, left: int, right: int) -> int:
+        """
+        切片  求和
+        :param left:
+        :param right:
+        :return:
+        """
+        if left == 0:
+            return self.nums[right]
+        return self.nums[right] - self.nums[left - 1]
+
+
+# Your NumArray object will be instantiated and called as such:
+# obj = NumArray(nums)
+# param_1 = obj.sumRange(left,right)
+if __name__ == '__main__':
+    result = NumArray([-2, 0, 3, -5, 2, -1]).sumRange(0, 2)
+    print(result)