POJ 1195 Mobile phones【 二维树状数组 】

题意：基础的二维数组，注意 0 + lowbit(0)会陷入无限循环-----

之前做一道一维的一直tle,就是因为这个--------------------------

#include<iostream>  
#include<cstdio>  
#include<cstring> 
#include <cmath> 
#include<stack>
#include<vector>
#include<map> 
#include<set>
#include<queue> 
#include<algorithm>  
using namespace std;

typedef long long LL;
const int INF = (1<<30)-1;
const int mod=1000000007;
const int maxn=1000005;

int c[1055][1055];
int n;

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

int sum(int x,int y){
    int ret = 0,y1;
    while(x > 0){
        y1 = y;
        while( y1 > 0){
            ret += c[x][y1];y1 -= lowbit(y1);
        }
        x-=lowbit(x);
    }
    return ret;
}

void add(int x,int y,int d){
    int y1;
    while(x <= n){
        y1 = y;
        while(y1 <= n){
            c[x][y1] += d; y1 += lowbit(y1);
        }
        x += lowbit(x);
    }
}

int main(){
    int cmd;
    while(scanf("%d %d",&cmd,&n) != EOF){
        memset(c,0,sizeof(c));
        while(scanf("%d",&cmd) != EOF && cmd != 3){
            if(cmd == 1){
                int x,y,d;
                scanf("%d %d %d",&x,&y,&d);x++;y++;
                add(x,y,d);
            }
            else{
                int x,y,xx,yy;
                int ret = 0;
                scanf("%d %d %d %d",&x,&y,&xx,&yy);
                x++;y++;xx++;yy++;
                ret = sum(xx,yy) - sum(x-1,yy) - sum(xx,y-1) + sum(x-1,y-1);
                printf("%d
",ret);
            }
        }
    }
    return 0;
}

话说好几天没有写代码了的说啊----

加油↖(^ω^)↗

goooooooooooooooooo----