Language: C++

#include<bits/stdc++.h>


#include <cassert>
#include <numeric>
#include <type_traits>

namespace atcoder {

namespace internal {

#ifndef _MSC_VER
template <class T>
using is_signed_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value ||
                                  std::is_same<T, __int128>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using is_unsigned_int128 =
    typename std::conditional<std::is_same<T, __uint128_t>::value ||
                                  std::is_same<T, unsigned __int128>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using make_unsigned_int128 =
    typename std::conditional<std::is_same<T, __int128_t>::value,
                              __uint128_t,
                              unsigned __int128>;

template <class T>
using is_integral = typename std::conditional<std::is_integral<T>::value ||
                                                  is_signed_int128<T>::value ||
                                                  is_unsigned_int128<T>::value,
                                              std::true_type,
                                              std::false_type>::type;

template <class T>
using is_signed_int = typename std::conditional<(is_integral<T>::value &&
                                                 std::is_signed<T>::value) ||
                                                    is_signed_int128<T>::value,
                                                std::true_type,
                                                std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<(is_integral<T>::value &&
                               std::is_unsigned<T>::value) ||
                                  is_unsigned_int128<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<
    is_signed_int128<T>::value,
    make_unsigned_int128<T>,
    typename std::conditional<std::is_signed<T>::value,
                              std::make_unsigned<T>,
                              std::common_type<T>>::type>::type;

#else

template <class T> using is_integral = typename std::is_integral<T>;

template <class T>
using is_signed_int =
    typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using is_unsigned_int =
    typename std::conditional<is_integral<T>::value &&
                                  std::is_unsigned<T>::value,
                              std::true_type,
                              std::false_type>::type;

template <class T>
using to_unsigned = typename std::conditional<is_signed_int<T>::value,
                                              std::make_unsigned<T>,
                                              std::common_type<T>>::type;

#endif

template <class T>
using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;

template <class T>
using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;

template <class T> using to_unsigned_t = typename to_unsigned<T>::type;

}  // namespace internal

}  // namespace atcoder

#include <cassert>
#include <vector>

namespace atcoder {

// Reference: https://en.wikipedia.org/wiki/Fenwick_tree
template <class T> struct fenwick_tree {
    using U = internal::to_unsigned_t<T>;

  public:
    fenwick_tree() : _n(0) {}
    fenwick_tree(int n) : _n(n), data(n) {}

    void add(int p, T x) {
        assert(0 <= p && p < _n);
        p++;
        while (p <= _n) {
            data[p - 1] += U(x);
            p += p & -p;
        }
    }

    T sum(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        return sum(r) - sum(l);
    }

  private:
    int _n;
    std::vector<U> data;

    U sum(int r) {
        U s = 0;
        while (r > 0) {
            s += data[r - 1];
            r -= r & -r;
        }
        return s;
    }
};

}  // namespace atcoder

using namespace std;
typedef long long ll;
constexpr int Inf = 2000000010;
constexpr ll INF= 2000000000000000000;
constexpr ll MOD = 1000000007;
const double PI = 3.1415926535897;
typedef pair<int,int> P;
typedef pair<int,P> PP;

template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}

template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}

ll mod(ll val, ll M) {
    ll res = val % M;
    if(res < 0) {
        res += M;
    }
    return res;
}

template<typename T>
T RS(T N, T P, T M){
    if(P == 0) {
        return 1;
    }
    if(P < 0) {
        return 0;
    }
    if(P % 2 == 0){
        ll t = RS(N, P/2, M);
        if(M == -1) return t * t;
        return t * t % M;
    }
    if(M == -1) {
        return N * RS(N,P - 1,M);
    }
    return N * RS(N, P-1, M) % M;
}

int main() {
    int N,Q;
    cin >> N >> Q;
    fenwick_tree<ll> fw(N);
    for(int i = 0;i < N;i++) {
        ll A;
        cin >> A;
        fw.add(i,A);
    }
    for(int i = 0;i < Q;i++) {
        int t;
        cin >> t;
        if(t == 0) {
            int p;
            ll x;
            cin >> p >> x;
            fw.add(p,x);
        }
        else {
            int l,r;
            cin >> l >> r;
            cout << fw.sum(l,r) << endl;
        }
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:197:5: error: 'fenwick_tree' was not declared in this scope; did you mean 'atcoder::fenwick_tree'?
  197 |     fenwick_tree<ll> fw(N);
      |     ^~~~~~~~~~~~
      |     atcoder::fenwick_tree
a.cc:105:27: note: 'atcoder::fenwick_tree' declared here
  105 | template <class T> struct fenwick_tree {
      |                           ^~~~~~~~~~~~
a.cc:197:20: error: expected primary-expression before '>' token
  197 |     fenwick_tree<ll> fw(N);
      |                    ^
a.cc:197:22: error: 'fw' was not declared in this scope
  197 |     fenwick_tree<ll> fw(N);
      |                      ^~