303. Range Sum Query - Immutable[E]

https://leetcode.com/problems/combination-sum/

Description

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.

Example:

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Given nums = [-2, 0, 3, -5, 2, -1]

sumRange(0, 2) -> 1
sumRange(2, 5) -> -1
sumRange(0, 5) -> -3

Note:

  1. You may assume that the array does not change.
  2. There are many calls to sumRange function.

Solution

https://leetcode.com/problems/range-sum-query-immutable/solution/

1

304. Range Sum Query 2D - Immutable[M]

https://leetcode.com/problems/range-sum-query-2d-immutable/

Description

Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2).

Range Sum Query 2D
The above rectangle (with the red border) is defined by (row1, col1) = (2, 1) and (row2, col2) = (4, 3), which contains sum = 8.

Example:

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Given matrix = [
  [3, 0, 1, 4, 2],
  [5, 6, 3, 2, 1],
  [1, 2, 0, 1, 5],
  [4, 1, 0, 1, 7],
  [1, 0, 3, 0, 5]
]

sumRegion(2, 1, 4, 3) -> 8
sumRegion(1, 1, 2, 2) -> 11
sumRegion(1, 2, 2, 4) -> 12

Note:

  1. You may assume that the matrix does not change.
  2. There are many calls to sumRegion function.
  3. You may assume that row1 ≤ row2 and col1 ≤ col2.

Solution

1

307. Range Sum Query - Mutable[M]

https://leetcode.com/problems/range-sum-query-mutable/

Description

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.

The update(i, val) function modifies nums by updating the element at index i to val.

Example:

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Given nums = [1, 3, 5]

sumRange(0, 2) -> 9
update(1, 2)
sumRange(0, 2) -> 8

Constraints:

  • The array is only modifiable by the update function.
  • You may assume the number of calls to update and sumRange function is distributed evenly.
  • 0 <= i <= j <= nums.length - 1

Solution

1