Codeforces: A. Roma and Lucky Numbers

The problem is from codeforces: http://www.codeforces.com/problemset/problem/262/A

#!/usr/bin/env python

n, k = map(int, raw_input().split())
s = raw_input().split()

ans = 0
for x in s:
    ans += 1 if x.count('4') + x.count('7') <= k else 0

print ans

Or a much shorter version.

N,K=map(int,raw_input().split())
print sum(i.count('4')+i.count('7')<=K for i in raw_input().split())

However, during the online contest, I wrote the solution in standard way, not using any benefits of Python programming language.

#!/usr/bin/env python

n, k = map(int, raw_input().split())
s = raw_input().split()

ans = 0
for x in s:
    j = 0
    for i in xrange(len(x)):
        t = x[i]
        if (t == '4') or (t == '7'):
            j += 1
            if (j > k): break
    if j <= k:
        ans += 1
print ans

–EOF (The Ultimate Computing & Technology Blog) —