Binary Indexed Tree 2D

    #include <cstdio>
    #include <cstdlib>
    #include <climits>
    #include <cstring>
    #include <algorithm>

    using namespace std;
    int map[1015][1015];

    void update(int x,int y, int n)
    {
        for(int i=x;i<=1005;i+=(i&(-i)))
        {
            for(int j=y;j<=1005;j+=(j&(-j)))
            {
                map[i][j]+=n;
            }
        }
    }

    int sum(int x,int y)
    {
        int s = 0;
        for(int i=x;i>=1;i-=(i&(-i)))
        {
            for(int j=y;j>=1;j-=(j&(-j)))
            {
                s+=map[i][j];
            }
        }
        return s;
    }

    int main(){
//        freopen("exp.in","r",stdin);
        int t, q;
        char s[3];
        int x1,x2,y1,y2,n1;
        scanf("%d",&t);
        for(int i=1;i<=t;i++)
        {
            printf("Case %d:\n",i);
            memset(map,0,sizeof(map));
            for(int j=1;j<=1005;j++)
                for(int k = 1;k<=1005;k++)
                    update(j,k,1);

            scanf("%d",&q);
            for(int j=1;j<=q;j++)
            {

                scanf("%s",s);
                if(s[0]=='S')
                {
                        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
                        if(x1>x2)   swap(x1,x2);
                        if(y1>y2)   swap(y1,y2);
                        printf("%d\n",sum(x2+1,y2+1)+sum(x1,y1)-sum(x1,y2+1)-sum(x2+1,y1));
                }
                else if(s[0]=='A')
                {
                        scanf("%d%d%d",&x1,&y1,&n1);
                        update(x1+1,y1+1,n1);
                }
                else if(s[0]=='D')
                {
                        scanf("%d%d%d",&x1,&y1,&n1);
                        int v = sum(x1+1,y1+1)+sum(x1,y1)-sum(x1,y1+1)-sum(x1+1,y1);
                        n1=(n1-v>0)?v:n1;
                        update(x1+1,y1+1,-n1);
                }
                else if(s[0]=='M')
                {
                        scanf("%d%d%d%d%d",&x1,&y1,&x2,&y2,&n1);
                        int v = sum(x1+1,y1+1)+sum(x1,y1)-sum(x1,y1+1)-sum(x1+1,y1);
                        n1=(n1-v)>0?v:n1;
                        update(x1+1,y1+1,-n1);
                        update(x2+1,y2+1,n1);
                }
            }
        }
//        fclose(stdin);
        return 0;
    }

Code From Hdu 1982