problem303

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303. Range Sum Query - Immutable (Easy)

Given an integer array nums, handle multiple queries of the following type:

1. 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]).

 

Example 1:

Input
["NumArray", "sumRange", "sumRange", "sumRange"]
[[[-2, 0, 3, -5, 2, -1]], [0, 2], [2, 5], [0, 5]]
Output
[null, 1, -1, -3]

Explanation
NumArray numArray = new NumArray([-2, 0, 3, -5, 2, -1]);
numArray.sumRange(0, 2); // return (-2) + 0 + 3 = 1
numArray.sumRange(2, 5); // return 3 + (-5) + 2 + (-1) = -1
numArray.sumRange(0, 5); // return (-2) + 0 + 3 + (-5) + 2 + (-1) = -3

 

Constraints:

• 1 <= nums.length <= 104
• -105 <= nums[i] <= 105
• 0 <= left <= right < nums.length
• At most 104 calls will be made to sumRange.

Related Topics

[Array] [Design] [Prefix Sum]

Similar Questions

1. Range Sum Query 2D - Immutable (Medium)
2. Range Sum Query - Mutable (Medium)
3. Maximum Size Subarray Sum Equals k (Medium)

Documentation

Index

• type NumArray
  • func Constructor(nums []int) NumArray
  • func (this *NumArray) SumRange(i int, j int) int

Types

type NumArray

type NumArray struct {
	// contains filtered or unexported fields
}

func Constructor

func Constructor(nums []int) NumArray

func (*NumArray) SumRange

func (this *NumArray) SumRange(i int, j int) int