树状数组模板程序

转自：http://blog.csdn.net/cnyali/article/details/50097455

#include<iostream>
#include<cstdio>
using namespace std;
int l;
int c[1000];
int lowbit(int x){
return x & (x ^ (x-1));
}
void up(int x,int y){
while(x<=l){
c[x]+=y;
x+=lowbit(x);
}
}
int cx(int x){
int sum=0;
int k=x;
while(k>0){
sum+=c[k];
k-=lowbit(k);
}
return sum;
}
int main(){
int i,j,k,m,n;
int x,y;
cin>>n>>m>>l;
for(i=1;i<=n;i++){
cin>>x>>y;
up(x,y);
}
for(i=1;i<=m;i++){
cin>>x>>y;
cout<<cx(y)-cx(x-1)<<endl;
}
return 0;
}