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 JAVA (judge verdict: Accepted)

import java.util.Scanner;

public class Main{
	static int n;
	static int[]a;
	static int []bit;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		int q = sc.nextInt();
		bit = new int[n + 1];
		a = new int[n + 1];
		for(int i = 0; i < q; i++) {
			int com = sc.nextInt();
			int x = sc.nextInt();
			int y = sc.nextInt();
			if(com == 0) {
				add(x, y);
			}else {
				System.out.println(sum(y) - sum(x - 1));
			}
		}
		sc.close();
	}
	static void add(int a, int w) {
		for(int x = a; x <= n; x += x & -x) {
			bit[x] += w;
		}
	}
	static int sum(int a) {
		int ret = 0;
		for(int x = a; x > 0; x -= x & -x) {
			ret += bit[x];
		}
		return ret;
	}
}