大佬们都好强啊，改完之后还是回去学线段树好了。。。lxl说树状数组先背下来就好了。。。
by mushroom_knight @ 2020-05-31 09:41:50
@[幽竹烟雨](/user/162203) 哦是这样才对
```cpp
int find(int x){
int ans=0;
for(;x;x-=lowbit(x)){
ans+=t[x];
}
return ans;
}
```
by 幽竹烟雨 @ 2020-05-31 09:42:07
@[Ace_Translator](/user/338786) 我谔谔
~~原来lxl的bit是背的，了解了~~
by Chthollytxdy @ 2020-05-31 09:42:52
@[Ace_Translator](/user/338786) 改好啦
```cpp
#include<bits/stdc++.h>
using namespace std;
int t[600001];
int a[500001];
int n,m;
int lowbit(int i){
return i&-i;
}
void modify(int x,int y){
for(;x<=n;x+=lowbit(x)){
t[x]+=y;
}
}
int find(int x){
int ans=0;
for(;x;x-=lowbit(x)){
ans+=t[x];
}
return ans;
}
void init(){
for(register int i=1;i<=n;++i){
modify(i,a[i]);
}
}
int cmd,x,y;
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin>>n>>m;
for(register int i=1;i<=n;++i){
cin>>a[i];
}
init();
for(register int i=1;i<=m;++i){
cin>>cmd>>x>>y;
if(cmd==1){
modify(x,y);
}
else{
cout<<find(y)-find(x-1)<<'\n';
}
}
return 0;
}
```
by 幽竹烟雨 @ 2020-05-31 09:43:05
然后modify也挂了
by SamariumPhosphide @ 2020-05-31 09:43:11
>@[Brian_WBY](/user/297433) #Q，找到问题了
by mushroom_knight @ 2020-05-31 09:44:03
@[Ace_Translator](/user/338786) 还是不熟,建议自己再多打几遍
by 幽竹烟雨 @ 2020-05-31 09:44:04
@[Chthollytxdy](/user/338442) lxl说的是我这种初学者先背下来。。。
by mushroom_knight @ 2020-05-31 09:44:49
@[幽竹烟雨](/user/162203) #Q
by mushroom_knight @ 2020-05-31 09:45:10
bushi您这种一看就知道是初入DS的
~~一入DS深似海，从此AC是路人~~
by Chthollytxdy @ 2020-05-31 09:48:49