Python练习题答案: 整数组合的总和【难度：2级】--景越Python编程实例训练营,1000道上机题等你来挑战

整数组合的总和【难度：2级】:

答案1：

from itertools import combinations_with_replacement

def find(arr,n):
    return sum( sum(c) == n for x in range(1,len(arr)+1) for c in combinations_with_replacement(arr, x) )​

答案2：

def find(arr,n):
    return(findl(arr,n,len(arr)))
def findl(arr,n,l):
    return(sum(findl(arr[1:],n-arr[0]*i,l-i) for i in range(l+1)) if ((arr) and (l>0)) else ((n==0) and (l>=0)))​

答案3：

from itertools import combinations_with_replacement as c

def find(arr, n):
    return sum(
        sum(xs) == n
        for i in range(len(arr))
        for xs in c(arr, i + 1)
    )​

答案4：

from itertools import combinations_with_replacement as cr
find=lambda a,n:sum(n==sum(c)for r in range(1,len(a)+1)for c in cr(a,r=r))​

答案5：

def N(Q,S,R,L,D,C,I) :
  if 0 < D and 0 < S :
    for I in range(I,L) :
      N(Q,S - Q[I],R,L,D - 1,C + (Q[I],),I)
  elif 0 == S :
    R.add(C)
  return R

def find (Q,S) :
  Q = sorted(set(Q))
  return len(N(Q,S,set(),len(Q),len(Q),(),0))​

答案6：

from itertools import combinations_with_replacement


def find(arr,n):
    ret = 0
    for i in range(1, len(arr) + 1):
        a = combinations_with_replacement(arr, i)
        ret += len([j for j in a if sum(j) == n])
    return ret​

答案7：

from itertools import combinations_with_replacement

def find(arr, n):    
    return sum(sum(x) == n for i in range(1, len(arr) + 1) for x in combinations_with_replacement(arr, i))​

答案8：

from itertools import combinations_with_replacement as cr

def find(arr,n):
    k=len(arr)
    return sum((1 for nn in range(k) for x in cr(arr,nn+1) if sum(x)==n))​

答案9：

from itertools import combinations_with_replacement as cr
def find(arr,n):
    k=len(arr)
    return len([x for nn in range(k) for x in cr(arr,nn+1) if sum(x)==n])​

答案10：

from itertools import combinations_with_replacement as cwr


def find(arr, n):
    all_combos = []
    for i in range(1, len(arr)+1):
        combos = list(cwr(arr, i))
        all_combos += combos
    c = 0
    for el in all_combos:
        if sum(el) == n:
            c += 1
    return c​