https://leetcode.com/problems/range-sum-query-immutable/ class NumArray { public: vector<int> vec; public: NumArray(vector<int> &nums) { if(nums.empty()) return; else { vec.push_back(nums[]); ;i<nums.size();++i) vec.push_back(vec[i-] +…

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. Example: Given nums = [-2, 0, 3, -5, 2, -1] sumRange(0, 2) -> 1 sumRange(2, 5) -> -1 sumRange(0, 5) -> -3 Note: You may assume that the array do…

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). The above rectangle (with the red border) is defined by (row1, col1) = (2, 1) and (row2, co…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 预先求和 相似题目 参考资料 日期 题目地址:https://leetcode.com/problems/range-sum-query-2d-immutable/description/ 题目描述 Given a 2D matrix matrix, find the sum of the elements inside the rectangle…

Range Sum Query 2D - Immutable 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). The above rectangle (with the red border) is defined by (row…

题意:查询一个数组在(i,j]范围内的元素的和. 思路非常简单,做个预处理,打个表就好 拓展:可以使用树状数组来完成该统计,算法复杂度为(logn),该数据结构强力的地方是实现简单,而且能完成实时更新以及上面的统计和 class NumArray { public: vector<int> sum; NumArray(vector<int> &nums) { sum.push_back(); ; i< nums.size(); ++i){ int m = sum[i]…

题目: Given an integer array nums, find the sum of the elements between indices iand j (i ≤ j), inclusive. Example: Given nums = [-2, 0, 3, -5, 2, -1] sumRange(0, 2) -> 1 sumRange(2, 5) -> -1 sumRange(0, 5) -> -3 Note: You may assume that the array…

翻译 给定一个整型数组nums,找出在索引i到j(i小于等于j)之间(包含i和j)的全部元素之和. 比如: 给定nums = [-2,0,3,-5,2,-1] sumRange(0, 2) -> 1 sumRange(2, 5) -> -1 sumRange(0, 5) -> -3 批注: 你能够假定这个数组不会改变. 这里会有非常多次对sumRange函数的调用. 原文 Given an integer array nums, find the sum of the elements…

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). The above rectangle (with the red border) is defined by (row1, col1) = (2, 1) and (row2, co…

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). The above rectangle (with the red border) is defined by (row1, col1) = (2, 1) and (row2, co…