POJ 1195-Mobile phones-二维树状数组

二维树状数组裸题

#include <cstdio>
#include <algorithm>
#include <cstring>

using namespace std;
const int maxn =1024+10;
int c[maxn][maxn];
int N;

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

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

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

int query(int l,int r,int u,int d)
{
    return getsum(r,u) - getsum(r,d-1) - getsum(l-1,u) + getsum(l-1,d-1);
}

int main()
{
    int op;
    int x,y,l,r,u,d;
    while(~scanf("%d",&op))
    {
        if(op == 0)
        {
            scanf("%d",&N);
            memset(c,0,sizeof c);
        }
        else if(op == 1)
        {
            scanf("%d%d%d",&x,&y,&u);
            update(x+1,y+1,u);
        }
        else if(op == 2)
        {
            scanf("%d%d%d%d",&l,&d,&r,&u);
            printf("%d
",query(l+1,r+1,u+1,d+1));
        }
        else if(op == 3)
        {
            break;
        }
    }
}