P3368 模板树状数组 2

Posted 2021-10-30 幽殇默

https://www.luogu.com.cn/problem/P3368

#include<bits/stdc++.h>
using namespace std;
const int N=1e5*5+10;
typedef long long int LL;
LL tr[N],a[N],n,m;
int lowbit(int x){return x&(-x);}
void add(int x,int c)
{
	for(int i=x;i<=n;i+=lowbit(i)) tr[i]+=c;
}
LL query(int x)
{
	LL res=0;
	for(int i=x;i;i-=lowbit(i)) res+=tr[i];
	return res;
}
int main(void)
{
	cin>>n>>m;
	for(int i=1;i<=n;i++) cin>>a[i];
	for(int i=1;i<=n;i++)
	{
		int b=a[i]-a[i-1];
		add(i,b);
	}
	while(m--)
	{
		int op; cin>>op;
		if(op==1)
		{
			int l,r,c; cin>>l>>r>>c;
			add(l,c),add(r+1,-c);
		}
		else 
		{
			int x; cin>>x;
			cout<<query(x)<<endl;
		}
	}
	return 0;
}