Problem:
Range Add Query (RAQ)

Write a program which manipulates a sequence A = {a1, a2, . . . , an} with the following operations:

add(s, t, x): add x to as, as+1, ..., at.

get(i): output the value of ai.

Note that the initial values of ai (i = 1, 2, . . . , n) are 0.

Input

n q
query1
query2
:
queryq

In the first line, n (the number of elements in A) and q (the number of queries) are given. Then, ith query queryi is given in the following format:

0 s t x

or

1 t

The first digit represents the type of the query. '0' denotes add(s, t, x) and '1' denotes get(i).

Output

For each get operation, print the value.

Constraints

1 ≤ n ≤ 100000

1 ≤ q ≤ 100000

1 ≤ s ≤ t ≤ n

1 ≤ i ≤ n

0 ≤ x ≤ 1000

Sample Input 1

3 5
0 1 2 1
0 2 3 2
0 3 3 3
1 2
1 3

Sample Output 1

3
5

Sample Input 2

4 3
1 2
0 1 4 1
1 2

Sample Output 2

0
1

Solution in Rust (judge verdict: Accepted)

use std::io;
use std::io::prelude::*;
use std::iter::repeat;

struct SegTree {
    n: usize,
    nodes: Vec<i32>,
}

impl SegTree {
    fn init(n: usize) -> SegTree {
        let n = 1 << f64::log2(n as f64).ceil() as usize;
        SegTree {
            n,
            nodes: repeat(0).take(2 * n - 1).collect(),
        }
    }

    fn add(&mut self, s: usize, t: usize, x: i32, ni: usize, l: usize, r: usize) {
        if r <= s || t <= l {
            return;
        }
        if s <= l && r <= t {
            self.nodes[ni] += x;
            return;
        }
        let m = (l + r) / 2;
        self.add(s, t, x, 2 * ni + 1, l, m);
        self.add(s, t, x, 2 * ni + 2, m, r);
    }

    fn get(&self, i: usize, ni: usize, l: usize, r: usize) -> i32 {
        self.nodes[ni] + if self.n - 1 <= ni {
            0
        } else {
            let m = (l + r) / 2;
            if i < m {
                self.get(i, 2 * ni + 1, l, m)
            } else {
                self.get(i, 2 * ni + 2, m, r)
            }
        }
    }
}

fn main() {
    let stdin = io::stdin();
    let mut lines = stdin.lock().lines();

    let line0 = lines.next().unwrap().unwrap();
    let n = line0.split_whitespace().next().unwrap().parse().unwrap();

    let mut mst = SegTree::init(n);

    for l in lines.map(Result::unwrap) {
        let mut words = l.split_whitespace();
        let com = words.next().unwrap().parse().unwrap();
        match com {
            0 => {
                let s: usize = words.next().unwrap().parse().unwrap();
                let t: usize = words.next().unwrap().parse().unwrap();
                let x = words.next().unwrap().parse().unwrap();
                let n = mst.n;
                mst.add(s - 1, t, x, 0, 0, n);
            }
            1 => {
                let i: usize = words.next().unwrap().parse().unwrap();
                println!("{}", mst.get(i - 1, 0, 0, mst.n));
            }
            _ => (),
        }
    }
}