Language: C++

// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma")
// #pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h>
#include <atcoder/fenwicktree>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace atcoder;
using namespace std;

#define fo(i,n)         for(int i=0;i<n;i++)
#define nl              "\n"
#define ff              first
#define ss              second
#define int             long long
#define pb              push_back
#define mp              make_pair
#define vec(x)          vector<x>
#define matrix(x)       vector<vector<x>>
#define sz(x)           (int)x.size()
#define mem(a,b)        memset(a, b, sizeof a)
#define vii             vector<pair<int,int>>
#define pii             pair<int,int>
#define vi              vector<int>
#define mii             map<int,int>
#define uii             unordered_map<int,int,custom_hash>
#define pqb             priority_queue<int>
#define pqs             priority_queue<int,vi,greater<int> >
#define gcd(a,b)        __gcd(a,b)
#define lcm(a,b)        (a*(b/gcd(a,b)))
#define setbits(x)      __builtin_popcountll(x)
#define zrobits(x)      __builtin_ctzll(x)
#define mod             1000000007
#define MOD             998244353
#define inf             1e18
#define ps(x,y)         fixed<<setprecision(y)<<x
#define mk(arr,n,type)  type *arr=new type[n];
#define w(x)            int x; cin>>x; while(x--)
#define all(v)          v.begin(),v.end()
#define rep(i,a,b)      for (int i = a; i<b; ++i)
#define len(s)          s.length()

#define watch(x)        cout << #x << " = " << x << endl

#define deb(...) cerr << "[" << #__VA_ARGS__ << "] : [", DBG(__VA_ARGS__)
void DBG() { cerr << "]\n";}
template<typename T, typename ...Args> void DBG(T first, Args... args)
{cerr << first; if(sizeof...(args))cerr<<", "; DBG(args...); }

mt19937                 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds; //for storing unique elements
typedef tree<int , null_type , less_equal<int> , rb_tree_tag , tree_order_statistics_node_update> ordered_set; //for repeating elements
 
int power(int a,int b,int m=mod)
{int ans=1;while(b>0){if(b&1)ans=(ans*a)%m;a=(a*a)%m;b>>=1;}
return ans;}

void babuBhaiya()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
}

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

const int N = 1e5+1;
const double pi = acos(-1);

void solve(){

    int n,q; cin>>n>>q;
    fenwicktree<int>f(n);
    fo(i,n){
        int a; cin>>a;
        f.add(i,a);
    }
    while(q--){
        int t; cin>>t;
        if(t == 0){
            int a, x; cin>>a>>x;
            f.add(a,x);
        }
        else{
            int l,r; cin>>l>>r;
            cout<<f.sum(l,r)<<"\n";
        }
    }
}

 
int32_t main()
{
    babuBhaiya();

    int t;

    t = 1;
    //cin>>t;

    while(t--){
        solve();
    }
    
    return 0;
}

Compiler output:
a.cc:6:10: fatal error: atcoder/fenwicktree: No such file or directory
    6 | #include <atcoder/fenwicktree>
      |          ^~~~~~~~~~~~~~~~~~~~~
compilation terminated.