Binary Indexed Tree is represented as an array. Let the array be BITree[]. Each node of Binary Indexed Tree stores sum of some elements of given array. Size of Binary Indexed Tree is equal to n where n is size of input array. In the below code, wehave used size as n+1 for ease...
Given a 2D matrixmatrix, 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, col2) =(4, 3), which co...
There are many calls to sumRegion function. You may assume that row1 ≤ row2 and col1 ≤ col2. 题意很简单,做法也很简单,把上一道题leetcode 303. Range Sum Query - Immutable 字串求和 + DP 做一下扩展即可。 代码如下: /* * 就是面积的迭代计算 * DP的一个简单应用 * */ class NumMatr...
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). Range Sum Query 2D The above rectangle (with the red border) is defined by (row1, col1) = (2, 1) and (row2, col2...
Leetcode: Range Sum Query 2D - Mutable && Summary: Binary Indexed Tree,参考:https://leetcode.com/discuss/72685/share-my-java-2-d-binary-indexed-tree-solutionBuildbinaryindexedtreetakes:O(mn*logm*logn)time,both upda
int sumRegion(int row1, int col1, int row2, int col2)Returns thesumof the elements ofmatrixinside the rectangle defined by itsupper left corner(row1, col1)andlower right corner(row2, col2). You must design an algorithm wheresumRegionworks onO(1)time complexity. ...
https://leetcode.com/problems/range-sum-query-2d-mutable/discuss/75870/Java-2D-Binary-Indexed-Tree-Solution-clean-and-short-17ms class NumMatrix { int N, M; int[][] bitTree; int[][] matrix; public NumMatrix(int[][] matrix) { if (matrix == null || matrix.length == 0 || matri...
https://leetcode.com/problems/range-sum-query-2d-mutable/description/ image.png 一般需要求一个区间的和,并且需要动态更新区间里的值。不是树状数组就是线段树了。这道题我用树状数组解了。 int[][]parent;int[][]ma;inth;intl;privateintlowbit(inti){returni&(-i);}privatevoidadd(inty,intx,intdel...
cpp Copy code class NumMatrix { public: vector<vector> pre_sum; NumMatrix(vector<vector<int>>& matrix) { // Check if the input matrix is empty if (matrix.empty() || matrix[0].empty()) return; int m = matrix.size(); int n = matrix[0].size(); ...
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). https://leetcode.com/static/i... The above rectangle (with the red border) is defined by (row1, col1) = (2, 1) ...