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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)


import java.util.*;

public class Main {
    int n, m, q;
    int[][] qArr;
    int max;
    List<Integer> list;
    void run() {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        m = sc.nextInt();
        q = sc.nextInt();
        qArr = new int[q][4];
        for (int i = 0; i < q; i++) {
            qArr[i] = new int[]{sc.nextInt() - 1, sc.nextInt() - 1, sc.nextInt(), sc.nextInt()};
        }

        for (int i = 0 ;i < m; i++) {
            list = new ArrayList<>();
            dfs(i);
        }

//        for (int bit = 0; bit < (1 << m); bit++) {
//            List<Integer> list = new ArrayList<>();
//            for (int i = 0; i < m; i++) {
//                if ((bit & (1 << i)) != 0) {
//                    list.add(i);
//                }
//            }
//            if (list.size() != n) {
//                continue;
//            }
//            debug(list);
//
//            int ans = 0;
//            for (int i = 0; i < q; i++) {
//                int[] arr = qArr[i];
//                if (list.get(arr[1]) - list.get(arr[0]) == arr[2]) {
////                    debug(arr);
//                    ans += arr[3];
//                }
//            }
//            max = Math.max(max, ans);
//        }

        System.out.println(max);
    }

    void dfs(int i) {
        list.add(i);
//        debug(list);
        if (list.size() == n) {
            int ans = 0;

            for (int j = 0; j < q; j++) {
//                debug("fuga");
                int[] arr = qArr[j];
                if (list.get(arr[1]) - list.get(arr[0]) == arr[2]) {
                    ans += arr[3];
                }
            }
            max = Math.max(max, ans);
//            debug("max", max, list);
            return;
        }
        for (int j = i ; j < m; j++) {
            dfs(j);
//            debug(j, list);
            list.remove(list.size() - 1);
        }
    }

    void debug(Object... os) {
        System.err.println(Arrays.deepToString(os));
    }

    public static void main(String[] args) {
        new Main().run();
    }
}