問題はこれ→https://atcoder.jp/contests/abc165/tasks/abc165_c
結構有名だと思う。

普通の解法

再帰関数を使う。
https://atcoder.jp/contests/abc165/submissions/37076168

n, m, q = map(int, input().split())
a, b, c, d = [0] * q, [0] * q, [0] * q, [0] * q
for i in range(q):
  a[i], b[i], c[i], d[i] = map(int, input().split())
  a[i] -= 1
  b[i] -= 1
def solve(x):
  res = 0
  if len(x) == n:
    for i in range(q):
      if x[b[i]] - x[a[i]] == c[i]:
        res += d[i]
    return res
  if len(x) == 0:
    bef = 1
  else:
    bef = x[-1]
  for i in range(bef, m + 1):
    res = max(res, solve(x + [i]))
  return res
print(solve([]))

多重for（タイピング力w）

Nの値で場合分け。

n, m, q = map(int, input().split())
a = []
b = []
c = []
d = []
for _ in range(q):
  A, B, C, D = map(int, input().split())
  A -= 1
  B -= 1
  a.append(A)
  b.append(B)
  c.append(C)
  d.append(D)
def score(t):
  res = 0
  for i, j, k, l in zip(a, b, c, d):
    if t[j] - t[i] == k:
      res += l
  return res
ans = 0
if n == 2:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      ans = max(ans, score([i0, i1]))
if n == 3:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        ans = max(ans, score([i0, i1, i2]))
if n == 4:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          ans = max(ans, score([i0, i1, i2, i3]))
if n == 5:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          for i4 in range(i3, m + 1):
            ans = max(ans, score([i0, i1, i2, i3, i4]))
if n == 6:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          for i4 in range(i3, m + 1):
            for i5 in range(i4, m + 1):
              ans = max(ans, score([i0, i1, i2, i3, i4, i5]))
if n == 7:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          for i4 in range(i3, m + 1):
            for i5 in range(i4, m + 1):
              for i6 in range(i5, m + 1):
                ans = max(ans, score([i0, i1, i2, i3, i4, i5, i6]))
if n == 8:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          for i4 in range(i3, m + 1):
            for i5 in range(i4, m + 1):
              for i6 in range(i5, m + 1):
                for i7 in range(i6, m + 1):
                  ans = max(ans, score([i0, i1, i2, i3, i4, i5, i6, i7]))
if n == 9:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          for i4 in range(i3, m + 1):
            for i5 in range(i4, m + 1):
              for i6 in range(i5, m + 1):
                for i7 in range(i6, m + 1):
                  for i8 in range(i7, m + 1):
                    ans = max(ans, score([i0, i1, i2, i3, i4, i5, i6, i7, i8]))
if n == 10:
  for i0 in range(1, m + 1):
    for i1 in range(i0, m + 1):
      for i2 in range(i1, m + 1):
        for i3 in range(i2, m + 1):
          for i4 in range(i3, m + 1):
            for i5 in range(i4, m + 1):
              for i6 in range(i5, m + 1):
                for i7 in range(i6, m + 1):
                  for i8 in range(i7, m + 1):
                    for i9 in range(i8, m + 1):
                      ans = max(ans, score([i0, i1, i2, i3, i4, i5, i6, i7, i8, i9]))
print(ans)

3021Byte。あー疲れた💦💦💦💦
今日もABC頑張るか