学步园

二维树状数组

注意求区间和 要分成多个部分来加减

还有就是 注意0的情况

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
int const MAXN = 1100;
int c[MAXN + 10][MAXN + 10],a[MAXN + 10][MAXN + 10];
int n,m;
int Lowbit(int x){
    return x &(-x);
}
void Add(int x,int y,int d){
    for(int i = x;i <= MAXN;i += Lowbit(i)){
        for(int j = y;j <= MAXN ;j += Lowbit(j)){
            c[i][j] += d;
        }
    }
}
int Sum(int x,int y){
    int ret = 0;
    for(int i = x;i > 0;i -= Lowbit(i)){
        for(int j = y;j > 0;j -= Lowbit(j)){
            ret += c[i][j];
        }
    }
    return ret;
}
int main(){
    while(~scanf("%d%d",&n,&m)){
        memset(c,0,sizeof(c));
        memset(a,0,sizeof(a));
        while(1){
            int flag;
            scanf("%d",&flag);
            if(flag == 3) break;
            if(flag == 1){
                int x,y,c1;
                scanf("%d%d%d",&x,&y,&c1);
                a[x + 2][y + 2] += c1;
                Add(x+2,y+2,c1);
            }
            else{
                int l,b,r,t;
                scanf("%d%d%d%d",&l,&b,&r,&t);
                printf("%d\n",Sum(r + 2,t + 2) - Sum(l + 1,t +2) - Sum(r + 2,b + 1) + Sum(l + 1,b + 1));
            }
        }
    }
    return 0;
}