problem303

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303. Range Sum Query - Immutable (Easy)

Given an integer array nums, find the sum of the elements 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 the nums array in the range [left, right] inclusive (i.e., sum(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 1 ((-2) + 0 + 3)
numArray.sumRange(2, 5); // return -1 (3 + (-5) + 2 + (-1)) 
numArray.sumRange(0, 5); // return -3 ((-2) + 0 + 3 + (-5) + 2 + (-1))

 

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

[Dynamic Programming]

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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