task_a_oleg.cpp

#include <iostream>
#include <vector>

using namespace std;

std::vector<long long> t(4 * 100000);

void build(int v, int vl, int vr)
{
    if (vl == vr)
    {
        t[v] = 0;
        return;
    }
    int vm = vl + (vr - vl) / 2;
    build(2 * v + 1, vl, vm);
    build(2 * v + 2, vm + 1, vr);
    t[v] = t[2 * v + 1] + t[2 * v + 2];
}

long long query(int v, int vl, int vr, int l, int r)
{
    if (r < vl || l > vr)
    {
        return 0;
    }
    if (l <= vl && vr <= r)
    {
        return t[v];
    }
    int vm = vl + (vr - vl) / 2;
    long long ql = query(2 * v + 1, vl, vm, l, r);
    long long qr = query(2 * v + 2, vm + 1, vr, l, r);
    return ql + qr;
}

void modify(int v, int vl, int vr, int pos, int value)
{
    if (vl == vr)
    {
        t[v] = value;
        return;
    }
    int vm = vl + (vr - vl) / 2;
    if (pos <= vm)
    {
        modify(2 * v + 1, vl, vm, pos, value);
    }
    else
    {
        modify(2 * v + 2, vm + 1, vr, pos, value);
    }
    t[v] = t [2 * v + 1] + t[2 * v + 2];
}

int main()
{
    int n, m;
    std::cin >> n >> m;
    build(0, 0, n);
    for (int i = 0; i < m; i++)
    {
        char command;
        int arg1, arg2;
        std::cin >> command >> arg1 >> arg2;
        switch(command)
        {
            case 'A':
                modify(0, 0, n, arg1, arg2);
                break;
            case 'Q':
                std::cout << query(0, 0, n, arg1, arg2);
                break;
        }
    }
    return 0;
}