Problem:
Score : 300 points

Problem Statement

Given are positive integers N, M, Q, and Q quadruples of integers ( a_i , b_i , c_i , d_i ).

Consider a sequence A satisfying the following conditions:

A is a sequence of N positive integers.

1 \leq A_1 \leq A_2 \le \cdots \leq A_N \leq M.

Let us define a score of this sequence as follows:

The score is the sum of d_i over all indices i such that A_{b_i} - A_{a_i} = c_i. (If there is no such i, the score is 0.)

Find the maximum possible score of A.

Constraints

All values in input are integers.

2 ≤ N ≤ 10

1 \leq M \leq 10

1 \leq Q \leq 50

1 \leq a_i < b_i \leq N ( i = 1, 2, ..., Q )

0 \leq c_i \leq M - 1 ( i = 1, 2, ..., Q )

(a_i, b_i, c_i) \neq (a_j, b_j, c_j) (where i \neq j)

1 \leq d_i \leq 10^5 ( i = 1, 2, ..., Q )

Input

Input is given from Standard Input in the following format:

N M Q
a_1 b_1 c_1 d_1
:
a_Q b_Q c_Q d_Q

Output

Print the maximum possible score of A.

Sample Input 1

3 4 3
1 3 3 100
1 2 2 10
2 3 2 10

Sample Output 1

110

When A = \{1, 3, 4\}, its score is 110. Under these conditions, no sequence has a score greater than 110, so the answer is 110.

Sample Input 2

4 6 10
2 4 1 86568
1 4 0 90629
2 3 0 90310
3 4 1 29211
3 4 3 78537
3 4 2 8580
1 2 1 96263
1 4 2 2156
1 2 0 94325
1 4 3 94328

Sample Output 2

357500

Sample Input 3

10 10 1
1 10 9 1

Sample Output 3

1

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

use std::cmp::max;
use proconio::input;


fn main() {
    input! {
        n: usize,
        m: i64,
        q: i64,
        data: [(usize, usize, i64, i64); q],
    }

    let candidates = gen(n, m, &mut vec![]);

    let mut ans = 0;
    for seq in candidates.iter() {
        ans = max(ans, points(&seq, &data));
    }

    println!("{:?}", ans);
}

fn gen(n: usize, m: i64, cur: &mut Vec<i64>) -> Vec<Vec<i64>> {
    if cur.len() >= n {
        return vec![cur.clone()];
    }

    let mut res = Vec::new();

    match cur.last() {
        Some(l) => {
            for v in *l..=m {
                cur.push(v);
                res.append(&mut gen(n, m, cur));
                cur.pop();
            }
        },
        None => {
            res.append(&mut gen(n, m, &mut vec![1]));
        }
    }

    res
}


fn points(seq: &Vec<i64>, data: &Vec<(usize, usize, i64, i64)>) -> i64 {
    let mut prev = seq[0];
    for &s in seq.iter() {
        if !(prev <= s) {
            return 0;
        }
        prev = s;
    }

    let mut res = 0;
    for (a, b, c, d) in data.iter() {
        if seq[b - 1] - seq[a - 1] == *c {
            res += d;
        }
    }

    res
}