树状数组单点修改区间查询

树状数组单点修改区间查询

// by spli
#include
#include
#include
#include
using namespace std;

const int N=500010;
int n,m;
int a[N],c[N];

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

void add(int pos,int v){
    for(int i=pos;i<=n;i+=lowbit(i))
        c[i]+=v;
}

int query(int x){
    int ret=0;
    for(int i=x;i>=1;i-=lowbit(i))
        ret+=c[i];
    return ret;
}

int main(){
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i) scanf("%d",&a[i]);
    for(int i=1;i<=n;++i) add(i,a[i]);
    int op,x,y;
    while(m--){
        scanf("%d%d%d",&op,&x,&y);
        if(op==1) add(x,y);
        else printf("%d\n",query(y)-query(x-1));
    }
    return 0;
}