ДО Снизу

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
#include <stack>
#include <bitset>
#include <map>
#include <ctime>
#include <numeric>


#ifndef M_PI
#define M_PI 3.141592653589
#endif
#define int long long
#define double long double

#ifdef TIME
#define start cin.tie(NULL); cout.tie(NULL); cout.setf(ios::fixed); cout.precision(10); ios_base::sync_with_stdio(false);int32_t START = clock()
#define finish cout << "\ntime: " << (clock() - START) / (CLOCKS_PER_SEC * 1.0); return 0
#endif

#ifndef TIME
#define start cin.tie(NULL); cout.tie(NULL); cout.setf(ios::fixed); cout.precision(10); ios_base::sync_with_stdio(false)
#define finish return 0
#endif

using namespace std;


//vector input
template<typename T>
istream &operator>>(istream &is, vector<T> &vec) {
    for (auto &i : vec) {
        cin >> i;
    }
    return is;
}

//pair output
template<typename E>
ostream &operator<<(ostream &os, pair<E, E> &t) {
    os << t.first << ' ' << t.second;
    return os;
}

//"map" pair output
template<typename E>
ostream &operator<<(ostream &os, pair<const E, E> &t) {
    os << t.first << ' ' << t.second;
    return os;
}

//vector output
template<typename T>
ostream &operator<<(ostream &os, vector<T> &vec) {
    for (T i : vec) {
        os << i << ' ';
    }
    return os;
}

//2 dimensional vector output
template<typename T>
ostream &operator<<(ostream &os, vector<vector<T> > &vec) {
    for (vector<T> i : vec) {
        os << i << '\n';
    }
    return os;
}

struct segtree {
    int n;
    vector<int> tree;

    segtree(vector<int> &a) {
        n = a.size();
        tree.resize(2 * n);
        for (int i = 0; i < n; ++i) {
            tree[n + i] = a[i];
        }
        for (int i = n - 1; i >= 1; --i) {
            tree[i] = tree[2 * i] + tree[2 * i + 1];
        }
    }

    void set(int i, int v) {
        i += n;
        tree[i] = v;
        i /= 2;
        while (i != 0) {
            tree[i] = tree[2 * i] + tree[2 * i + 1];
            i /= 2;
        }
    }

    int get(int l, int r) {
        l += n;
        r += n;
        int ans = 0;
        while (l <= r) {
            if (l % 2 == 1) {
                ans += tree[l];
                l += 1;
            }
            if (r % 2 == 0) {
                ans += tree[r];
                r -= 1;
            }
            l /= 2;
            r /= 2;
        }
        return ans;
    }
};

int32_t main() {
    start;

    int n, m;
    cin >> n >> m;
    vector<int> a(n);
    cin >> a;
    segtree sgt(a);

    while (m--) {
        int op;
        cin >> op;
        if (op == 1) {
            int i, v;
            cin >> i >> v;
            sgt.set(i, v);
        } else {
            int l, r;
            cin >> l >> r;
            cout << sgt.get(l, r - 1) << '\n';
        }
    }

    finish;
}