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 Python (judge verdict: Accepted)

import sys
import itertools

class RSQ:
    def __init__(self, n):
        self.sz = 1
        self.inf = (1 << 31) - 1
        while self.sz <= n: self.sz = self.sz << 1
        self.dat = [0] * (2 * self.sz - 1)
    
    def update(self, idx, x):
        idx += self.sz - 1
        self.dat[idx] += x
        while idx > 0:
            idx = (idx - 1) >> 1
            self.dat[idx] += x
            
    def query(self, a, b):
        return self.query_help(a, b, 0, 0, self.sz)
            
    def query_help(self, a, b, k, l, r):
        if r <= a or b <= l:
            return 0
        elif a <= l and r <= b:
            return self.dat[k]
        else:
            return self.query_help(a, b, 2 * k + 1, l, (l + r)>>1) + \
                    self.query_help(a, b, 2 * k + 2, (l + r) >> 1, r)
    
    
if __name__ == '__main__':
    line = sys.stdin.readline()
    n, q = line.split()
    n, q = int(n), int(q)
    rmq = RSQ(n)
    
    for i in range(q):
        line = sys.stdin.readline()
        op, a, b = line.split()
        op, a, b = int(op), int(a), int(b)
        if op == 0: 
            rmq.update(a, b)
        else: 
            sys.stdout.write(str(rmq.query(a, b + 1)) + '\n')