树状数组模板1——单点修改区间查询

树状数组的模板，修改单点的值，查询某个区间

 

#include<cstdio>
#include<cctype> 
using namespace std;

int c[500010],n,m;

int read()
{
    int x=0,f=1;
    char c=getchar();
    while (!isdigit(c))
        f=c=='-'?-1:1,c=getchar();
    while (isdigit(c))
        x=(x<<1)+(x<<3)+(c^48),c=getchar();
    return x*f;
}

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

int query(int x)
{
    int ans=0;
    for (;x;x-=lowbit(x))
        ans+=c[x];
    return ans;
}

int update(int x,int val)
{
    for (;x<=n;x+=lowbit(x))
        c[x]+=val;
}

int main()
{
    int i,j,t;
    n=read(),m=read();
    for (i=1;i<=n;i++)
    {
        j=read();
        update(i,j);
    }
    while (m--)
    {
        t=read();
        i=read();
        j=read();
        if (t==1)
            update(i,j);
        else
            printf("%d
",query(j)-query(i-1));
    }
    return 0;
}