poj 1195 Mobile phones

 1 #include<cstdio>
 2 #include<cstring>
 3 const int maxn=1024+5;
 4 int s[maxn][maxn];
 5 int n;
 6 int lowbit(int x)
 7 {
 8     return x&-x;
 9 }
10 long long sum(int x,int y)
11 {
12     long long  ret=0;
13     for(int i=x;i>0;i-=lowbit(i))
14         for(int j=y;j>0;j-=lowbit(j))
15         ret+=s[i][j];
16     return ret;
17 }
18 void add(int x,int y,int inc)
19 {
20    for(int i=x;i<=n;i+=lowbit(i))
21     for(int j=y;j<=n;j+=lowbit(j))
22      s[i][j]+=inc;
23 }
24 int main()
25 {
26         int com;
27         int a,b,c,d;
28         while(scanf("%d",&com)&&com!=3)
29         {
30             if(com==0)
31             {
32                 scanf("%d",&n);
33                 memset(s,0,sizeof(s));
34             }
35             else if(com==1)
36             {
37                 scanf("%d%d%d",&a,&b,&c);
38                 add(a+1,b+1,c);
39             }
40             else if(com==2)
41             {
42                 scanf("%d%d%d%d",&a,&b,&c,&d);
43                 long long  ans=sum(c+1,d+1)+sum(a,b)-sum(c+1,b)-sum(a,d+1);
44                 printf("%lld
",ans);
45             }
46         }
47     return 0;
48 }