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 <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <climits>
#include <utility>

typedef long long ll;
using namespace std;

struct RSQ{
  //Ranged Sum Query

  int n;
  vector<int> node;
  //1-indexed

  RSQ(int size){
    int t=1;
    while(t<size){
      t*=2;
    }

    node.clear();
    node.resize(t*2,0);
    n=t;
  }

  void add(int i,int val){
    i=i+n;
    while(i>0){
      node[i]+=val;
      i/=2;
    }
  }

  int getSum(int s,int t,int k=1,int left=0,int right=-1){
    if(right<0)right=n;

    if(right<=s||left>=t){
      return 0;
    }

    if(left>=s&&right<=t){
      return node[k];
    }

    return getSum(s,t,k*2,left,(left+right)/2)+getSum(s,t,k*2+1,(left+right)/2,right);
  }
};

int main(void){
  int n,q,c,x,y,i;
  cin>>n>>q;

  RSQ tree(n);

  for(i=0;i<q;i++){
    scanf("%d %d %d",&c,&x,&y);
    //cin>>c>>x>>y;
    x--;
    if(c==0){
      tree.add(x,y);
    }
    else{
      printf("%d\n",tree.getSum(x,y));
    }
  }

  return 0;
}