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;

template <typename T>
struct BinaryIndexedTree {
    vector<T> data;

    BinaryIndexedTree(int sz) { data.assign(++sz, 0); }

    T sum(int k) {
        T ret = 0;
        for (++k; k > 0; k -= k & -k) ret += data[k];
        return ret;
    }

    void add(int k, T x) {
        for (++k; k < data.size(); k += k & -k) data[k] += x;
    }
};

int main() {
    int n, q;
    cin >> n >> q;
    BinaryIndexedTree<int> bit(n);
    for (int i = 0; i < q; i++) {
        int com, x, y;
        cin >> com >> x >> y;
        if (com == 0) {
            x--;
            bit.add(x, y);
        } else {
            x--;
            y--;
            int sum = bit.sum(y);
            if (x > 0) sum -= bit.sum(x - 1);
            cout << sum << endl;
        }
    }
}