题目
Given an integer array nums, handle multiple queries of the following type:
- Calculate the sum of the elements of nums between indices left and right inclusive where left <= right. Implement the NumArray class:
- NumArray(int[] nums) Initializes the object with the integer array nums.
- int sumRange(int left, int right) Returns the sum of the elements of nums between indices left and right inclusive (i.e. nums[left] + nums[left + 1] + … + nums[right]).
解题思路
前缀和
代码
class NumArray:
def __init__(self, nums: List[int]):
self.prefix_sum = [0]
for n in nums:
self.prefix_sum.append(self.prefix_sum[-1] + n)
def sumRange(self, left: int, right: int) -> int:
return self.prefix_sum[right + 1] - self.prefix_sum[left]
