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  3. Project Euler #53: Combinatoric selections
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Project Euler #53: Combinatoric selections

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19 Discussions

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  • angadsingh1729
     + 0 comments

    Short and simple:

    def Solve_Prob(n,k):

        count = 0
for i in range(2,n+1):
    x = i
    for r in range(1,(n//2)+1):
        if x > k:
            count = count + (i-2*r+1)
            break
        x = (x*(i-r))//(r+1)
answer = count
return answer

    t = 1 for i in range(0,t): n,k = map(int, input().split()) answer = Solve_Prob(n,k) print(answer)

  • srikv
     + 0 comments
    # Enter your code here. Read input from STDIN. Print output to STDOUT
import math

n, k = map(int, input().split())

def combi(n, r):
    if r == 0 or r == n:
        return(1)
    s, r = 1, (n-r if n-r < r else r)
    for i in range(r):
        s *= ((n-i) / (i+1))
    return(math.ceil(s))
 
c = 0
for i in range(1, n+1):
    for j in range(i+1):
        if combi(i, j) > k:
            c += 1

print(c)

  • Venkateshgurram5
     + 0 comments

    Easy.

    import math
n,k=map(int,input().strip().split())
count=0
for i in range(1,n+1):
    for r in range(n):
        if math.comb(i,r)>k:
            count+=1
print(count)

  • vidush_rk11
     + 0 comments

    100 points/- python3

    from math import comb
data=input().split()
n=int(data[0])
k=int(data[1])

count=0
for i in range(2,n+1):
    r=(i+1)//2
    if comb(i,r)>k:
        if i%2==0:
            count+=1
            r=r-1
        else:
            count+=2
            r=r-2

        while comb(i,r)>k:
            count+=2
            r+=-1
            if r<0:
                break

print(count)

  • daveveitch
     + 0 comments

    Hint: one does not have to compute all nCr but rather consider how nCr changes as n and r changes.