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 <stdio.h>

int main() {
  int n, q, i, j, command, x, y, sum;

  scanf("%d %d", &n, &q);

  int nums[n];
  memset(nums, 0, sizeof(nums));

  for (i = 0; i < q; i++) {
    scanf("%d %d %d", &command, &x, &y);
    if (command) {
      sum = 0;
      for (j = x - 1; j < y; j++)
	sum += nums[j];
      
      printf("%d\n", sum);
    } else {
      nums[x - 1] += y;
    }
  }
}