树状数组支持两种操作: Add(x, d)操作:   让a[x]增加d. Query(L,R): 计算 a[L]+a[L+1]……a[R]. 当要频繁的对数组元素进行修改,同时又要频繁的查询数组内任一区间元素之和的时候,可以考虑使用树状数组. 通常对一维数组最直接的算法可以在O(1)时间内完成一次修改,但是需要O(n)时间来进行一次查询.而树状数组的修改和查询均可在O(log(n))的时间内完成. 在二维情况下:数组A[][]的树状数组定义为: C[x][y] = ∑ a[i][j], 其中, …

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…

Mobile phones Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 14391   Accepted: 6685 Description Suppose that the fourth generation mobile phone base stations in the Tampere area operate as follows. The area is divided into squares. The…

题链: http://poj.org/problem?id=1195 题解: 二维树状数组 #include<cstdio> #include<cstring> #include<iostream> #define MAXN 1500 using namespace std; struct BIT{ int val[MAXN][MAXN],N; void Reset(int n){N=n; memset(val,0,sizeof(val));} int Lowbit(i…

Description Suppose that the fourth generation mobile phone base stations in the Tampere area operate as follows. The area is divided into squares. The squares form an S * S matrix with the rows and columns numbered from 0 to S-1. Each square contain…

                                                              Mobile phones Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 18608   Accepted: 8621 Description Suppose that the fourth generation mobile phone base stations in the Tampere a…

Description Suppose that the fourth generation mobile phone base stations in the Tampere area operate as follows. The area is divided into squares. The squares form an S * S matrix with the rows and columns numbered from 0 to S-1. Each square contain…

Description Suppose that the fourth generation mobile phone base stations in the Tampere area operate as follows. The area is divided into squares. The squares form an S * S matrix with the rows and columns numbered from 0 to S-1. Each square contain…

Mobile phones Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 16893   Accepted: 7789 Description Suppose that the fourth generation mobile phone base stations in the Tampere area operate as follows. The area is divided into squares. The…

<题目链接> 题目大意: 一个由数字构成的大矩阵,开始是全0,能进行两种操作1) 对矩阵里的某个数加上一个整数(可正可负)2) 查询某个子矩阵里所有数字的和要求对每次查询,输出结果 解题分析: 二维树状数组模板题,需要注意的是,由于题目给的x,y坐标可以为0,所以我们应该将这些点的坐标全部+1,然后就是查询指定子矩阵中所有元素之和,很直观的就能得到式子 ans=sum(x2,y2)-sum(x1-1,y2)-sum(x2,y1-1)+sum(x1-1,y1-1). #include <c…