线段树 建树 单点修改 点点/区间查询

#include<bits/stdc++.h>
using namespace std;
const int maxn=10000+10;
int a[maxn],sum[maxn*4];     //四倍空间
inline int read(){     //快读，没啥特殊意思
	int s=0,w=1;
	char ch=getchar();
	while(ch<=‘0‘ || ch>‘9‘){if(ch==‘-‘)w=-1;ch=getchar();}
	while(ch>=‘0‘ && ch<=‘9‘){s=s*10+ch-48;ch=getchar();}
	return s*w;
}
inline void pushup(int root){ //这个节点的值是该节点的左节点加右节点的和
	sum[root] = sum[root<<1]+sum[root<<1|1];
}//乘2是该节点的左节点，再加1则是右节点
inline void build(int l,int r,int root){//建树 
	if(l == r){
		sum[root] = a[l];
		return;
	}
	int mid = (l+r)>>1;
	build(l,mid,root<<1);
	build(mid+1,r,root<<1|1);
	pushup(root);
}
inline void update(int l,int r,int root,int num,int w){//更新 
	if(l == r){
		sum[root] += w;
		return;
	}
	int mid = (l+r)>>1;
	if(num <= mid)update(l,mid,root<<1,num,w);
	if(num > mid)update(mid+1,r,root<<1|1,num,w);
	pushup(root);
}
inline int query(int l,int r,int root,int num){//查询
	if(l == r)return sum[root];
	int mid = (l+r)>>1;
	if(num <= mid)return query(l,mid,root<<1,num);
	if(num > mid)return query(mid+1,r,root<<1|1,num);
}
inline int query2(int root,int l,int r,int L,int R){//区间查询
    if(L <= l && r <= R)
        return sum[root];
    int mid = (l+r)>>1,tmp = 0;
    if(L <= mid)
        tmp += query2(root<<1,l,mid,L,R);
    if(mid < R)
        tmp += query2(root<<1|1,mid+1,r,L,R);
    return tmp;
}
int main(){
	int n;
	n = read();
	for(int i = 1;i <= n;i++)scanf("%d",&a[i]);
	build(1,n,1);
//	for(int i = 1;i <= n*2-1;i++)printf("%d%c",sum[i],i == n?‘\n‘:‘ ‘);
	for(int i = 1,op,x,y,L,R;i <= 10;i++){
		scanf("%d",&op);
		if(op == 1)scanf("%d%d",&x,&y),update(1,n,1,x,y);
		if(op == 2)scanf("%d",&x),printf("%d\n",query(1,n,1,x)); 
		if(op == 3)scanf("%d%d",&L,&R),printf("%d\n",query2(1,1,n,L,R));
	}
	return 0;
}