POJ1195 Mobile phones 【二维树状数组】

Mobile phones
Time Limit: 5000MS   Memory Limit: 65536K
Total Submissions: 14288   Accepted: 6642

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 contains a base station. The number of active mobile phones inside a square can change because a phone is moved from a square to another or a phone is switched on or off. At times, each base station reports the change in the number of active phones to the main base station along with the row and the column of the matrix. 

Write a program, which receives these reports and answers queries about the current total number of active mobile phones in any rectangle-shaped area. 

Input

The input is read from standard input as integers and the answers to the queries are written to standard output as integers. The input is encoded as follows. Each input comes on a separate line, and consists of one instruction integer and a number of parameter integers according to the following table. 
POJ1195 Mobile phones 【二维树状数组】_第1张图片
The values will always be in range, so there is no need to check them. In particular, if A is negative, it can be assumed that it will not reduce the square value below zero. The indexing starts at 0, e.g. for a table of size 4 * 4, we have 0 <= X <= 3 and 0 <= Y <= 3. 

Table size: 1 * 1 <= S * S <= 1024 * 1024 
Cell value V at any time: 0 <= V <= 32767 
Update amount: -32768 <= A <= 32767 
No of instructions in input: 3 <= U <= 60002 
Maximum number of phones in the whole table: M= 2^30 

Output

Your program should not answer anything to lines with an instruction other than 2. If the instruction is 2, then your program is expected to answer the query by writing the answer as a single line containing a single integer to standard output.

Sample Input

0 4
1 1 2 3
2 0 0 2 2 
1 1 1 2
1 1 2 -1
2 1 1 2 3 
3

Sample Output

3
4

【问题描述】

假设第四代移动电话的收发站是这样运行。整个区域被分割成很小的方格。所有的方格组成了一个S*S的矩阵,行和列从0~S-1编号。每个小方格都包含一个收发站。每个方格内的手机的移动电话数量可以不断改变,因为手机用户在各个方格之间移动,也有用户开机或者关机。一旦某个方格里面开机的移动电话数量发生了变化,该方格里的收发站就会向总部发送一条信息说明这个改变量。

总部要你写一个程序,用来管理从各个收发站收到的信息。老板可能随时会问:某个给定矩形区域内有多少部开机的移动电话啊?你的程序必须要能随时回答老板的问题。

【输入输出数据】

从标准输入读入整数,向标准输出写入你对老板的回答。

输入数据的格式如下:每个输入独立成一行。一个输入包括一个指示数和一些参数,见下表:

指示数

参数

意义

0

S

初始指令。整个区域由S*S个小方格组成。这个指令只会在一开始出现一次。

1

X Y A

方格(XY)内的开机移动电话量增加了AA可能是正数也可能是负数

2

L B R T

询问在矩形区域(L,B)(R,T)内有多少部开机的移动电话。矩形区域(L,B)(R,T)包括所有的格子(XY)满足L<=X<=R,B<=Y<=T.

3

 

终止程序。这个指令只会在最后出现一次。

所有的数据总是在给定范围内,你不需要差错。特别的,如果A是负数,你可以认为该操作不会让该格子的开机移动电话数变成负数。格子是从0开始编号的,比如一个4*4的区域,所有的格子(XY)应该表示为:0<=X<=3,0<=Y<=3

对于除了2之外的指示,你的程序不应该输出任何东西。如果指示是2,那么你的程序应该向标准输出写入一个整数。

【数据限制】

区域大小 

S * S

1 * 1 <= S * S <= 1024 * 1024

每个格子的值

V

0 <= V <= 32767

增加/减少量

A

-32768 <= A <= 32767

指令总数

U

3 <= U <= 60002

所有格子的和

M

M= 2^30


第一次在OJ题中用函数指针数组,感觉挺简洁的。

#include <stdio.h>

int tree[1030][1030], size;

int lowBit(int n)
{
	return n & (-n);
}

void getSize()
{
	scanf("%d", &size);
}

void update()
{
	int x, y, val;
	scanf("%d%d%d", &x, &y, &val);
	++x; ++y;
	
	int temp;
	while(x <= size){
		temp = y;
		while(temp <= size){
			tree[x][temp] += val;
			temp += lowBit(temp);
		}
		x += lowBit(x);
	}
}

int getSum(int x, int y)
{
	int sum = 0, temp;
	while(x > 0){
		temp = y;
		while(temp > 0){
			sum += tree[x][temp];
			temp -= lowBit(temp);
		}
		x -= lowBit(x);
	}
	return sum;
}

void query()
{
	int x1, y1, x2, y2;
	scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
	++x1; ++y1; ++x2; ++y2;
	
	int sum = getSum(x2, y2) - getSum(x2, y1 - 1) - 
		getSum(x1 - 1, y2) + getSum(x1 - 1, y1 - 1);
	printf("%d\n", sum);
}

void (*funArr[])() = {
	getSize, update, query
}; //函数指针数组

int main()
{
	int com;
	while(scanf("%d", &com), com != 3)
		(*funArr[com])();	
	return 0;
}


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