leetcode

0 class NumArray {

1 vector<int> prefix;

2

3 public:

4 NumArray(const vector<int> &nums) : prefix(size(nums) + 1) {

5 for (int i = 0, acc = 0; i < size(nums); i++) {

6 prefix[i + 1] = acc += nums[i];

7 }

8 }

9

10 int sumRange(int left, int right) const { return prefix[right + 1] - prefix[left]; }

11 };