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++ (judge verdict: Accepted)

#include<iostream>
#include<vector>
#include<algorithm>
#include<climits>
#include<string>
 
const int MAX_N=1<<17;
 
using namespace std;
 
int n,bit[MAX_N+1];
 
int sum(int i){
  int s=0;
  while(i>0){
    s+=bit[i];
    i-=i&-i;
  }
  return s;
}
 
void add(int i,int x){
  while(i<=n){
    bit[i]+=x;
    i+=i&-i;
  }
}
 
int main(void){
 
  int q,com,a,b;
 
  cin >> n >> q;
  n++;
  while(q--){
    cin >> com >> a >> b;
    if(com)cout << sum(b)-sum(a-1) << endl;
    else add(a,b);
  }
 
  return 0;
}