Combinatoric selections :Problem 53
There are exactly ten ways of selecting three from five, 12345:
In general,
It is not until n = 23, that a value exceeds one-million: 23C10 = 1144066.
How many, not necessarily distinct, values of nCr, for 1 ≤ n ≤ 100, are greater than one-million?
Problem Source : Euler Project
Python Code:
def combinatoricSelection():
def binomial(n,k):
if k < 2:
if k == 1:
return n
else:
return 1
else:
return (n*binomial(n-1,k-1))/k
n = 23
counter = 0
for i in range(78):
i = i + n
for j in range (i):
if binomial(i,j) > 1000000:
counter = counter + 1
print counter
combinatoricSelection()
123, 124, 125, 134, 135, 145, 234, 235, 245, and 345
In combinatorics, we use the notation, 5C3 = 10.In general,
nCr = |
n!
r!(n−r)! |
,where r ≤ n, n! = n×(n−1)×...×3×2×1, and 0! = 1. |
How many, not necessarily distinct, values of nCr, for 1 ≤ n ≤ 100, are greater than one-million?
Problem Source : Euler Project
Python Code:
def combinatoricSelection():
def binomial(n,k):
if k < 2:
if k == 1:
return n
else:
return 1
else:
return (n*binomial(n-1,k-1))/k
n = 23
counter = 0
for i in range(78):
i = i + n
for j in range (i):
if binomial(i,j) > 1000000:
counter = counter + 1
print counter
combinatoricSelection()
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