hdu 2642 star（二维树状数组）

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2642点击打开链接

Stars

Time Limit: 5000/2000 MS (Java/Others)    Memory Limit: 32768/65536 K (Java/Others)
Total Submission(s): 1830    Accepted Submission(s): 781

Problem Description

Yifenfei is a romantic guy and he likes to count the stars in the sky.
To make the problem easier,we considerate the sky is a two-dimension plane.Sometimes the star will be bright and sometimes the star will be dim.At first,there is no bright star in the sky,then some information will be given as "B x y" where 'B' represent bright and x represent the X coordinate and y represent the Y coordinate means the star at (x,y) is bright,And the 'D' in "D x y" mean the star at(x,y) is dim.When get a query as "Q X1 X2 Y1 Y2",you should tell Yifenfei how many bright stars there are in the region correspond X1,X2,Y1,Y2.

There is only one case.

 

Input

The first line contain a M(M <= 100000), then M line followed.
each line start with a operational character.
if the character is B or D,then two integer X,Y (0 <=X,Y<= 1000)followed.
if the character is Q then four integer X1,X2,Y1,Y2(0 <=X1,X2,Y1,Y2<= 1000) followed.

 

Output

For each query,output the number of bright stars in one line.

 

Sample Input

5B 581 145B 581 145Q 0 600 0 200D 581 145Q 0 600 0 200

 

Sample Output

10

题意：基础的树状数组操作 注意0，0就好 用book判断有没有已经亮了

#include <bits/stdc++.h>using namespace std;int tree[1111][1111];int book[1111][1111];int lowbit (int x){    return x&-x;}int getsum(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+=tree[i][j];    return sum;}void add(int x,int y,int num){        for(int i=x;i<=1000;i+=lowbit(i))            for(int j=y;j<=1000;j+=lowbit(j))                tree[i][j]+=num;        book[x][y]+=num;}int main(){    int n=0;    cin >> n ;    memset(tree,0,sizeof(tree));    while(n--)    {        char c;        cin >> c;        if(c=='Q')        {            int x1,x2,y1,y2;            cin >> x1 >> x2 >> y1 >> y2;            if(x1>x2)                swap(x1,x2);            if(y1>y2)                swap(y1,y2);            cout << getsum(x2+1,y2+1)-getsum(x1,y2+1)-getsum(x2+1,y1)+getsum(x1,y1) << endl;        }        else if(c=='B')        {            int x,y;            cin >> x >> y ;            if(!book[x+1][y+1])                add(x+1,y+1,1);        }        else if(c=='D')        {            int x,y;            cin >> x >> y ;            if(book[x+1][y+1])                {                    add(x+1,y+1,(-1));                }        }    }}