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 <bits/stdc++.h>
using namespace std;
int bit[100000];
int n;
void add(int a,int x){
	while(a<=n){
		bit[a]+=x;
		a+=a&-a;
	}
}
int sum(int a){
	int ans=0;
	while(a){
		ans+=bit[a];
		a-=a&-a;
	}
	return ans;
}
int main(){
	int q;	cin>>n>>q;
	while(q--){
		int c,x,y;	cin>>c>>x>>y;
		if(c==0)	add(x,y);
		else if(c==1)	cout<<sum(y)-sum(x-1)<<endl;
	}
	return 0;
}