https://blog.csdn.net/qq_34990731/article/details/82889654
https://www.luogu.org/problemnew/show/P3368
#include<iostream>
#include<cstdio>
using namespace std;
int b[500100],n,c[500100];
int lowbit(int i)//树状数组尝龟操作
{
return i&(-i);
}
void change(int i,int num)
{
while(i<=n)
{
b[i]+=num;//b储存的是修改的值
i+=lowbit(i);
}
return ;
}
int sum(int i)
{
int ans=0;
while(i>0)
{
ans+=b[i];
i-=lowbit(i);
}
return ans;
}
int main()
{
int m;
scanf("%d %d",&n,&m);
for(int i=1;i<=n;i++)
{
scanf("%d",&c[i]);//输入数据
}
for(int i=1;i<=m;i++)
{
int d,x,y,k;
scanf("%d",&d);
if(d==1)
{
scanf("%d %d %d",&x,&y,&k);//修改区间
change(x,k);
change(y+1,-k);
}
else
{
scanf("%d",&x);
int ans;
ans=sum(x);//单点查询
printf("%d \n",ans+c[x]);
}
}
return 0;
}