Mobile phones--树状数组

Mobile phones

Time Limit: 5000MS Memory Limit: 65536KTotal Submissions: 18824 Accepted: 8685

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. 

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 41 1 2 32 0 0 2 2 1 1 1 21 1 2 -12 1 1 2 3 3

Sample Output

34

题目链接：http://poj.org/problem?id=1195

最近刚刚学了树状数组，是不是时间有点晚。。。学弟们都学了，以前以为会了线段树就不用学树状数组，但是学了才发现真的比线段树好写，拼手速的方法啊。

题目大意很简单，树状数组入门题，树状数组不懂的去学。。。有两种操作，1是增加xin[i][j]的值，2是查询x1,y1,x2,y2的这个矩阵的和，二维树状数组，以为我不会二维线段树，就GG了，所以只能上树状数组了。

代码：

#include <cstdio>#include <cstring>#include <iostream>using namespace std;int xin[2333][2333];int n;int lowbit(int x){    return x&(-x);}void add(int x,int y,int val){    for(int i=x;i<=n;i+=lowbit(i)){        for(int j=y;j<=n;j+=lowbit(j)){            xin[i][j]+=val;        }    }    return ;}int query(int x,int y){    int sum=0;    for(int i=x;i>0;i-=lowbit(i)){        for(int j=y;j>0;j-=lowbit(j)){            sum+=xin[i][j];        }    }    return sum;}int main(){    int t;    scanf("%d%d",&t,&n);    int q;    memset(xin,0,sizeof(xin));    while(scanf("%d",&q)&&q<3){        if(q==1){            int x,y,z;            scanf("%d%d%d",&x,&y,&z);            x++;            y++;            add(x,y,z);        }        else if(q==2){            int a,b,c,d;            scanf("%d%d%d%d",&a,&b,&c,&d);            a++;            b++;            c++;            d++;            printf("%d\n",query(c,d)-query(c,b-1)-query(a-1,d)+query(a-1,b-1));        }    }    return 0;}