| | | 1 | | // -------------------------------------------------------------------------------- |
| | | 2 | | // Copyright (C) 2025 Eugene Eremeev (also known as Yevhenii Yeriemeieiv). |
| | | 3 | | // All Rights Reserved. |
| | | 4 | | // -------------------------------------------------------------------------------- |
| | | 5 | | // This software is the confidential and proprietary information of Eugene Eremeev |
| | | 6 | | // (also known as Yevhenii Yeriemeieiv) ("Confidential Information"). You shall not |
| | | 7 | | // disclose such Confidential Information and shall use it only in accordance with |
| | | 8 | | // the terms of the license agreement you entered into with Eugene Eremeev (also |
| | | 9 | | // known as Yevhenii Yeriemeieiv). |
| | | 10 | | // -------------------------------------------------------------------------------- |
| | | 11 | | |
| | | 12 | | namespace LeetCode.Algorithms.RangeSumQueryImmutable; |
| | | 13 | | |
| | | 14 | | /// <inheritdoc /> |
| | | 15 | | public class RangeSumQueryImmutablePrefixSum : IRangeSumQueryImmutable |
| | | 16 | | { |
| | | 17 | | private readonly int[] _prefixSum; |
| | | 18 | | |
| | | 19 | | /// <summary> |
| | | 20 | | /// Time complexity - O(n) |
| | | 21 | | /// Space complexity - O(n) |
| | | 22 | | /// </summary> |
| | | 23 | | /// <param name="nums"></param> |
| | 1 | 24 | | public RangeSumQueryImmutablePrefixSum(int[] nums) |
| | 1 | 25 | | { |
| | 1 | 26 | | _prefixSum = new int[nums.Length + 1]; |
| | | 27 | | |
| | 14 | 28 | | for (var i = 0; i < nums.Length; i++) |
| | 6 | 29 | | { |
| | 6 | 30 | | _prefixSum[i + 1] = _prefixSum[i] + nums[i]; |
| | 6 | 31 | | } |
| | 1 | 32 | | } |
| | | 33 | | |
| | | 34 | | /// <summary> |
| | | 35 | | /// Time complexity - O(1) |
| | | 36 | | /// Space complexity - O(1) |
| | | 37 | | /// </summary> |
| | | 38 | | /// <param name="left"></param> |
| | | 39 | | /// <param name="right"></param> |
| | | 40 | | /// <returns></returns> |
| | | 41 | | public int SumRange(int left, int right) |
| | 3 | 42 | | { |
| | 3 | 43 | | return _prefixSum[right + 1] - _prefixSum[left]; |
| | 3 | 44 | | } |
| | | 45 | | } |