树状数组

//最基本的树状数组#include<iostream> #include<cstring>#define size 1000using namespace std;int A[size],C[size],N;void add(int x,int d);int lowbit(int x);int sum(int x);void build();int lowbit(int x)   //求x得二进制表达式中最右边的1对应的值（不是序号）{    return x&-x;}void build()  //初始化数组{    for(int i=1;i<=N;i++)    {        add(i,A[i]);    }}void add(int x,int d)  //在X的位置加上大小为d的数{    while(x<=N)    {        C[x]+=d;        x+=lowbit(x);    }}int sum(int x)  //求1到X的和{    int ret=0;    while(x>=1)    {        ret+=C[x];        x=x-lowbit(x);    }    return ret;}int main(){    cin>>N;    memset(C,0,sizeof(C));    for(int i=1;i<=N;i++)    {        cin>>A[i];    }    build();    for(int i=1;i<=N;i++)    {        cout<<C[i]<<" ";    }    cout<<endl;    for(int i=1;i<=N;i++)    {        cout<<sum(i)<<" ";    }    cout<<endl;    return 0;}