Problem:
Range Sum Query

Write a program which manipulates a sequence A = {a1, a2, . . . , an} with the following operations:

add(i, x): add x to ai.

getSum(s, t): print the sum of as, as+1,...,at.

Note that the initial values of ai (i = 1, 2, . . . , n) are 0.

Input

n q
com1 x1 y1
com2 x2 y2
...
comq xq yq

In the first line, n (the number of elements in A) and q (the number of queries) are given. Then, q queries are given where com represents the type of queries. '0' denotes add(xi, yi) and '1' denotes getSum(xi, yi).

Output

For each getSum operation, print the sum in a line.

Constraints

1 ≤ n ≤ 100000

1 ≤ q ≤ 100000

If comi is 0, then 1 ≤ xi ≤ n, 0 ≤ yi ≤ 1000.

If comi is 1, then 1 ≤ xi ≤ n, 1 ≤ yi ≤ n.

Sample Input 1

3 5
0 1 1
0 2 2
0 3 3
1 1 2
1 2 2

Sample Output 1

3
2

Solution in C++14 (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define dump(...)
#endif
#define endl "\n"
#define ll long long
#define int ll
#define BUF 1e5
#define INF 1LL << 30
#define vi vector<int>
#define vvi vector<vector<int>>
#define all(a) (a).begin(), (a).end()
#define bit(n) (1LL << (n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
constexpr ll mod = 1e9 + 7;
ll A, B, C, D, G, H, N, M, L, K, P, Q, R, W, X, Y, Z;
string S, T;
ll ans = 0;

template <typename T>
istream &operator>>(istream &is, vector<T> &vec) {
    for (T &x : vec)
        is >> x;
    return is;
}

template <typename Monoid>
class SegmentTree {
public:
    using F = function<Monoid(Monoid, Monoid)>;

    vector<int> node;
    int size;
    int n;
    F f;
    Monoid ie;

    SegmentTree(vector<int> &in, F f, Monoid ie) : f(f), ie(ie) {
        int in_sz = in.size();
        n = 1;
        while (n < in_sz) {
            n *= 2;
        }
        size = n * 2 - 1;
        node.resize(size, 0);
        for (int i = 0; i < in_sz; i++) {
            node[n - 1 + i] = in[i];
        }
        init_dfs(0);
    }

    int init_dfs(int now) {
        if (2 * now + 1 >= size)
            return node[now];
        node[now] = f(init_dfs(2 * now + 1), init_dfs(2 * now + 2));
        return node[now];
    }

    void add(int index, int val) {
        index += n - 1;
        node[index] += val;
        while (index > 0) {
            index = (index - 1) / 2;
            node[index] = f(node[2 * index + 1], node[2 * index + 2]);
        }
    }

    void update(int index, int val) {
        index += n - 1;
        node[index] = val;
        while (index > 0) {
            index = (index - 1) / 2;
            node[index] = f(node[2 * index + 1], node[2 * index + 2]);
        }
    }

    int query(int a, int b) {
        return _query(a, b, 0, 0, n);
    }

    int _query(int a, int b, int now, int l, int r) {
        if (r <= a || b <= l)
            return ie;
        if (a <= l && r <= b)
            return node[now];
        int val_l = _query(a, b, 2 * now + 1, l, (l + r) / 2);
        int val_r = _query(a, b, 2 * now + 2, (l + r) / 2, r);
        return f(val_l, val_r);
    }
};

signed main() {
    cin >> N >> Q;
    int ie = 0;
    vector<int> v(N, ie);
    SegmentTree<int> sg(v, [](int x, int y) { return x + y; }, ie);
    for (int q = 0; q < Q; q++) {
        int c, x, y;
        cin >> c >> x >> y;
        if (c == 0) {
            sg.add(x - 1, y);
        } else {
            cout << sg.query(x - 1, y) << endl;
        }
    }
}