给定一个整数数组 nums
,处理以下类型的多个查询:
- 计算索引
left
和right
(包含left
和right
)之间的nums
元素的 和 ,其中left <= right
实现 NumArray
类:
NumArray(int[] nums)
使用数组nums
初始化对象int sumRange(int i, int j)
返回数组nums
中索引left
和right
之间的元素的 总和 ,包含left
和right
两点(也就是nums[left] + nums[left + 1] + ... + nums[right]
)
示例 1:
输入: ["NumArray", "sumRange", "sumRange", "sumRange"] [[[-2, 0, 3, -5, 2, -1]], [0, 2], [2, 5], [0, 5]] 输出: [null, 1, -1, -3]解释: 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))
提示:
1 <= nums.length <= 104
-105 <= nums[i] <= 105
0 <= i <= j < nums.length
- 最多调用
104
次sumRange
方法
问题简要描述:实现 NumArray
类
Java
class NumArray {private int[] s;public NumArray(int[] nums) {int n = nums.length;s = new int[n + 1];for (int i = 0; i < n; i++) {s[i + 1] = s[i] + nums[i];}}public int sumRange(int left, int right) {return s[right + 1] - s[left];}
}/*** Your NumArray object will be instantiated and called as such:* NumArray obj = new NumArray(nums);* int param_1 = obj.sumRange(left,right);*/
Python3
class NumArray:def __init__(self, nums: List[int]):self.s = list(accumulate(nums, initial=0))def sumRange(self, left: int, right: int) -> int:return self.s[right + 1] - self.s[left]# Your NumArray object will be instantiated and called as such:
# obj = NumArray(nums)
# param_1 = obj.sumRange(left,right)
TypeScript
class NumArray {private s; constructor(nums: number[]) {let n = nums.length;this.s = Array(n + 1).fill(0);for (let i = 0; i < n; i++) {this.s[i + 1] = this.s[i] + nums[i];}}sumRange(left: number, right: number): number {return this.s[right + 1] - this.s[left]; }
}/*** Your NumArray object will be instantiated and called as such:* var obj = new NumArray(nums)* var param_1 = obj.sumRange(left,right)*/