树状数组(BIT)是一个查询和修改复杂度都为log(n)的数据结构,主要用于查询任意两位之间的所有元素之和,其编程简单,很容易被实现.而且可以很容易地扩展到二维.让我们来看一道很裸的二维树状数组题: 在一个“打鼹鼠”的游戏中,鼹鼠会不时地从洞中钻出来,不过不会从洞口钻进去(鼹鼠真胆大……).洞口都在一个大小为n(n<=1024)的正方形中.这个正方形在一个平面直角坐标系中,左下角为(0,0),右上角为(n-1,n-1).洞口所在的位置都是整点,就是横纵坐标都为整数的点.而SuperBrother…

题目链接 裸二维树状数组 #include <bits/stdc++.h> const int N = 305; struct BIT_2D { int c[105][N][N], n, m; void init(int n, int m) { memset (c, 0, sizeof (c)); this->n = n; this->m = m; } void updata(int k, int x, int y, int z) { for (int i=x; i<=n;…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=1559 最大子矩阵 Time Limit: 30000/10000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2901    Accepted Submission(s): 1454 Problem Description 给你一个m×n的整数矩阵,在上面找一个x×y的子矩阵,使…

Matrix Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 22058   Accepted: 8219 Description Given an N*N matrix A, whose elements are either 0 or 1. A[i, j] means the number in the i-th row and j-th column. Initially we have A[i, j] = 0 (1…

Mobile phones Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 14489   Accepted: 6735 Description Suppose that the fourth generation mobile phone base stations in the Tampere area operate as follows. The area is divided into squares. The…

D. Iahub and Xors   Iahub does not like background stories, so he'll tell you exactly what this problem asks you for. You are given a matrix a with n rows and n columns. Initially, all values of the matrix are zeros. Both rows and columns are 1-based…

题意:给你一个n*n的全0矩阵,每次有两个操作: C x1 y1 x2 y2:将(x1,y1)到(x2,y2)的矩阵全部值求反 Q x y:求出(x,y)位置的值 树状数组标准是求单点更新区间求和,但是我们处理一下就可以完美解决此问题.区间更新可以使用区间求和的方法,在更新的(x2,y2)记录+1,在更新的(x1-1,y1-1)-1(向前更新到最前方).单点求和就只需要与区间更新相反,向后求一个区间和.这样做的理由是:如果求和的点在某次更新范围内,我们+1但是不执行-1,否者要么都不执行,要么都…

Matrix Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 25004   Accepted: 9261 Description Given an N*N matrix A, whose elements are either 0 or 1. A[i, j] means the number in the i-th row and j-th column. Initially we have A[i, j] = 0 (1…

Matrix Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 17224   Accepted: 6460 Description Given an N*N matrix A, whose elements are either 0 or 1. A[i, j] means the number in the i-th row and j-th column. Initially we have A[i, j] = 0 (1…

题目:http://poj.org/problem?id=2155 中文题意: 给你一个初始全部为0的n*n矩阵,有如下操作 1.C x1 y1 x2 y2 把矩形(x1,y1,x2,y2)上的数全部取反,1->0,0->1 2.Q x y 求n*n矩阵的(x,y)位置上的数 题解: 先看简单的: 给你一个初始全为0的长度为n的序列,有如下操作 1.C x y 把序列x到y位取反1->0,0->1 2.Q x 求序列第x位的数 做法很简单,设计一个数组a[],a[1..i]的和表示…