Problem:
Score : 400 points

Problem Statement

Given is a string S consisting of digits from 1 through 9.

Find the number of pairs of integers (i,j) (1 ≤ i ≤ j ≤ |S|) that satisfy the following condition:

Condition: In base ten, the i-th through j-th characters of S form an integer that is a multiple of 2019.

Constraints

1 ≤ |S| ≤ 200000

S is a string consisting of digits from 1 through 9.

Input

Input is given from Standard Input in the following format:

S

Output

Print the number of pairs of integers (i,j) (1 ≤ i ≤ j ≤ |S|) that satisfy the condition.

Sample Input 1

1817181712114

Sample Output 1

3

Three pairs - (1,5), (5,9), and (9,13) - satisfy the condition.

Sample Input 2

14282668646

Sample Output 2

2

Sample Input 3

2119

Sample Output 3

0

No pairs satisfy the condition.

Solution in Rust (1.42.0) (judge verdict: Accepted)

fn main() {
    let s: Vec<u8> = read::<String>().bytes().collect();
    let mut mod_t = vec![0];
    let mut sum = 0;
    let mut base = 1;
    let mut ma: HashMap<usize, usize> = HashMap::new();
    ma.insert(0, 1);
    for i in (0..s.len()).rev() {
        sum += base * (s[i] - b'0') as usize;
        sum %= 2019;
        mod_t.push(sum);
        match ma.get_mut(&sum) {
            Some(v) => *v += 1,
            None => {
                ma.insert(sum, 1);
            }
        }
        base *= 10;
        base %= 2019;
    }
    let mut ans = 0;
    for (_, v) in ma {
        ans += v * (v - 1) / 2;
    }
    println!("{}", ans);
}

// =========
#[allow(unused_imports)]
use std::cmp::{max, min};
#[allow(unused_imports)]
use std::collections::{HashMap, HashSet};
#[allow(unused_imports)]
use std::process::exit;

#[allow(dead_code)]
const MOD: usize = 1000000007;

fn read<T: std::str::FromStr>() -> T {
    use std::io::Read;
    let stdin = std::io::stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

// =========