poj 2155 matrix

彻底弄懂二维树状数组

http://www.java3z.com/cwbwebhome/article/article1/1369.html?id=4804

09年国家集训队武森《浅谈信息学竞赛中的“0” 和“ 1”》的论文

http://wenku.baidu.com/link?url=Nl7I-GFx9wN1SiHSmOT9RDQ-1Aesr3aAhKImIzlsLqSI7ZCfQcwmWjO_IYN1-j6D2WRluAkQRywTJdJvS1UAgusX8JdhKDtBEM5ovpM9Cxy

#include <iostream>
#include <cstdio>
#include <cstring>
#define N 1002
using namespace std;
int g[N][N];

inline int lowbit(int x)
{
    return x&-x;
}

void add(int x,int y)
{
    int i,j;
    for(i=x;i<N;i+=lowbit(i))
        for(j=y;j<N;j+=lowbit(j))
            g[i][j]++;
}

int sum(int x,int y)
{
    int i,j,res=0;
    for(i=x;i>0;i-=lowbit(i))
        for(j=y;j>0;j-=lowbit(j))
            res+=g[i][j];
    return res;
}

void run()
{
    int n,_;
    int x1,x2,y1,y2;
    char c;
    scanf("%d%d",&n,&_);
    memset(g,0,sizeof(g));
    while(_--)
    {
        scanf("%c%c",&c,&c);
        if(c=='C')
        {
            scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
            add(x1,y1);
            add(x2+1,y1);
            add(x1,y2+1);
            add(x2+1,y2+1);
        }
        else
        {
            scanf("%d%d",&x1,&y1);
            printf("%d
",sum(x1,y1)%2);
        }
    }
    cout<<endl;
}

int main()
{
    int _;
    scanf("%d",&_);
    while(_--)
        run();
    return 0;
}