## 代码1：(函数全在结构体内)
```cpp
#include <iostream>
#include <cstdio>
using namespace std;
struct node{
int l , r , val;
node *lson , *rson;
node(int L = 0 , int R = 0 , int VAL = 0 , node* LSON = NULL , node* RSON = NULL):l(L),r(R),val(VAL),lson(LSON),rson(RSON){};
};
struct tree{
node *root = new node;
node* buildl(node *x){
if (x -> lson) return x -> lson;
return x -> lson = new node(x -> l , (x -> l + x -> r) >> 1);
}
node* buildr(node *x){
if (x -> rson) return x -> rson;
return x -> rson = new node(((x -> l + x -> r) >> 1) + 1 , x -> r);
}
void pushup(node *x){
x -> val = 0;
if (x -> lson) x -> val += x -> lson -> val;
if (x -> rson) x -> val += x -> rson -> val;
}
void build(int l , int r){
*root = node(l , r);
}
void update(node *x , int pos , int d){
int l = x -> l , r = x -> r;
if (l == r){
x -> val += d;
return;
}
int m = l + r >> 1;
if (pos <= m) update(buildl(x) , pos , d);
else update(buildr(x) , pos , d);
pushup(x);
}
int query(node *x , int a , int b){
int l = x -> l , r = x -> r;
if (a <= l && r <= b) return x -> val;
int m = l + r >> 1;
int ans = 0;
if (a <= m) ans += query(buildl(x) , a , b);
if (m < b) ans += query(buildr(x) , a , b);
return ans;
}
};
tree t;
int n,m;
int main(){
cin >> n >> m;
t.build(1 , n);
int x,y,z;
for (int i = 1;i <= n;i++){
cin >> x;
t.update(t.root , i , x);
}
while (m--){
cin >> x >> y >> z;
if (x == 1){
t.update(t.root , y , z);
}
else{
cout << t.query(t.root , y , z) << '\n';
}
}
return 0;
}
```
## 代码2:（函数有的在结构体内，有的在结构体外）
```cpp
#include <iostream>
#include <cstdio>
using namespace std;
struct node{
int l , r , val;
node *lson , *rson;
node(int L = 0 , int R = 0 , int VAL = 0 , node* LSON = NULL , node* RSON = NULL):l(L),r(R),val(VAL),lson(LSON),rson(RSON){};
};
struct tree{
node *root = new node;
node* buildl(node *x){
if (x -> lson) return x -> lson;
return x -> lson = new node(x -> l , (x -> l + x -> r) >> 1);
}
node* buildr(node *x){
if (x -> rson) return x -> rson;
return x -> rson = new node(((x -> l + x -> r) >> 1) + 1 , x -> r);
}
void pushup(node *x){
x -> val = 0;
if (x -> lson) x -> val += x -> lson -> val;
if (x -> rson) x -> val += x -> rson -> val;
}
void build(int l , int r){
*root = node(l , r);
}
void update(node *x , int pos , int d){
int l = x -> l , r = x -> r;
if (l == r){
x -> val += d;
return;
}
int m = l + r >> 1;
if (pos <= m) update(buildl(x) , pos , d);
else update(buildr(x) , pos , d);
pushup(x);
}
int query(node *x , int a , int b){
int l = x -> l , r = x -> r;
if (a <= l && r <= b) return x -> val;
int m = l + r >> 1;
int ans = 0;
if (a <= m) ans += query(buildl(x) , a , b);
if (m < b) ans += query(buildr(x) , a , b);
return ans;
}
};
tree t;
int n,m;
int main(){
cin >> n >> m;
t.build(1 , n);
int x,y,z;
for (int i = 1;i <= n;i++){
cin >> x;
t.update(t.root , i , x);
}
while (m--){
cin >> x >> y >> z;
if (x == 1){
t.update(t.root , y , z);
}
else{
cout << t.query(t.root , y , z) << '\n';
}
}
return 0;
}
```
## 代码3：（函数全在结构体外）
```cpp
#include <iostream>
#include <cstdio>
using namespace std;
struct node{
int l , r , val;
node *lson , *rson;
node(int L = 0 , int R = 0 , int VAL = 0 , node* LSON = NULL , node* RSON = NULL):l(L),r(R),val(VAL),lson(LSON),rson(RSON){};
};
struct tree{
node *root = new node;
void build(int l , int r){
*root = node(l , r);
}
};
node* buildl(node *x){
if (x -> lson) return x -> lson;
return x -> lson = new node(x -> l , (x -> l + x -> r) >> 1);
}
node* buildr(node *x){
if (x -> rson) return x -> rson;
return x -> rson = new node(((x -> l + x -> r) >> 1) + 1 , x -> r);
}
void pushup(node *x){
x -> val = 0;
if (x -> lson) x -> val += x -> lson -> val;
if (x -> rson) x -> val += x -> rson -> val;
}
void update(node *x , int pos , int d){
int l = x -> l , r = x -> r;
if (l == r){
x -> val += d;
return;
}
int m = l + r >> 1;
if (pos <= m) update(buildl(x) , pos , d);
else update(buildr(x) , pos , d);
pushup(x);
}
int query(node *x , int a , int b){
int l = x -> l , r = x -> r;
if (a <= l && r <= b) return x -> val;
int m = l + r >> 1;
int ans = 0;
if (a <= m) ans += query(buildl(x) , a , b);
if (m < b) ans += query(buildr(x) , a , b);
return ans;
}
tree t;
int n,m;
int main(){
cin >> n >> m;
t.build(1 , n);
int x,y,z;
for (int i = 1;i <= n;i++){
cin >> x;
update(t.root , i , x);
}
while (m--){
cin >> x >> y >> z;
if (x == 1){
update(t.root , y , z);
}
else{
cout << query(t.root , y , z) << '\n';
}
}
return 0;
}
```
by Michael2012 @ 2024-08-21 21:53:19
@[Michael2012](/user/689640) 应该是的，大概是玄学常数
还有之前某同学写了一个大概是 `for` 里面嵌套判断函数，每循环一边调用一次判断函数，然后 T 了，结果把函数里的代码直接复制到 `for` 循环内就 A 了，差不多也是玄学常数
by No_Rest @ 2024-08-21 22:05:24
@[ldf1208](/user/550821) 很多 STL 和 C++ 自带的东西似乎常数都不小
by No_Rest @ 2024-08-21 22:07:11