hdu 2642

这题应该就是标准的二维树状数组，应该没什么难度

处理一下x,y等于0的情况就过了

#include <iostream>

#include <cstdio>

#include <cstring>

#include <string>

using namespace std;

const int maxn = 1e3+;

int c[maxn][maxn];

bool map[maxn][maxn];

void add(int x,int y,int d);

int getsum(int x,int y);

int main()

{

    int t,x1,y1,x2,y2;

    while(scanf("%d",&t) != EOF)

    {

        memset(c, , sizeof(c));

        memset(map, false, sizeof(map));

        while(t--)

        {

            string a;

            cin >> a;

            if(a == "B")

            {

                scanf("%d%d",&x1,&y1);

                x1 ++; y1 ++;

                if(map[x1][y1])

                    continue;

                add(x1, y1, );

                map[x1][y1] = true;

            }

            else if(a == "D")

            {

                scanf("%d%d",&x1,&y1);

                x1 ++; y1 ++;

                if(!map[x1][y1])

                    continue;

                add(x1, y1, -);

                map[x1][y1] = false;

            }

            else

            {

                scanf("%d%d%d%d",&x1,&x2,&y1,&y2);

                x1 ++; y1 ++; x2 ++; y2 ++;

                if(x1>x2)swap(x1,x2);

                if(y1>y2)swap(y1,y2);

                int k = getsum(x2, y2) + getsum(x1-, y1-) - getsum(x1-,y2) - getsum(x2, y1-);

                printf("%d\n",k);

            }

        }

    }

}

int lowbit(int k)

{

    return k&(-k);

}

void add(int x,int y,int d)

{

    int i,j;

    for(i=x;i<maxn;i+=lowbit(i))

    {

        for(j=y;j<maxn;j+=lowbit(j))

        {

            c[i][j] += d;

        }

    }

}

int getsum(int x,int y)

{

    int i,j;

    int sum = ;

    for(i=x;i>;i-=lowbit(i))

        for(j=y;j>;j-=lowbit(j))

            sum += c[i][j];

    return sum;

}