6/11 每日一題(自定義)

 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.

-------

class NumArray:

    def __init__(self, nums: List[int]):

        self.nums=nums #將一個整數列表nums作為參數儲存在self.nums中

       

    def sumRange(self, left: int, right: int) -> int:

        #選取範圍內的list

        range_arry=self.nums[left:right+1]

        return sum(range_arry) #返回範圍內的列表總和

       

# Your NumArray object will be instantiated and called as such:

# obj = NumArray(nums)

# param_1 = obj.sumRange(left,right)

--參考解答

class NumArray:

    def __init__(self, nums: List[int]):
        arr = [nums[0]]
        for i in range(1,len(nums)):
            arr.append(arr[-1]+nums[i])
        self.arr = arr

        

    def sumRange(self, left: int, right: int) -> int:
        if left == 0:
            return self.arr[right]
        return self.arr[right] - self.arr[left - 1]

------------

class NumArray:

    def __init__(self, nums: List[int]):
        self.nums=[0]+list(accumulate(nums))
        print(self.nums)

    def sumRange(self, left: int, right: int) -> int:
        return self.nums[right+1]-self.nums[left]

# Your NumArray object will be instantiated and called as such:
# obj = NumArray(nums)
# param_1 = obj.sumRange(left,right)