[Solved] Hackerrank Code not working [closed]

Question

There are several things wrong with your program.

First the insert method doesn’t do what you seem to think it does.

list.insert(i, x)

Insert an item at a given position. The first argument is the index of the element before which to insert, so a.insert(0, x) inserts at the front of the list, and a.insert(len(a), x) is equivalent to a.append(x).

Second, you’re attempting to count every time a letter appears at all, not just the first instance in a line.

This also looks like a low effort question, which is why you’re getting downvoted. What have you tried?

Here’s a solution that uses your method correctly, but it’s still not a very pythonic approach. Have you considered using a dict to keep track of this information instead?

num = raw_input()
li = list()
count = 150*[0]
seen = 150*[False]
ans = 0

while num > 0:
    li.append(raw_input())
    num = int(num)-1

for i in range(0, len(li)):
    for j in range(0, len(li[i])):
        if (not seen[ord(li[i][j])]):
            count[ord(li[i][j])] += 1
        seen[ord(li[i][j])] = True
    seen = 150*[False]

print count
for i in range(0, len(count)):
    if count[i] == len(li):
        ans = ans+1
        print chr(i)
print ans

Here’s the same approach using more pythonic language, isn’t this much easier to understand?

num = raw_input()
lines = []
seen = set()
count = {}

while num > 0:
    lines.append(raw_input())
    num = int(num)-1

for line in lines:
    for char in line:
        if (char not in seen):
            count[char] = count.get(char, 0) + 1
        seen.add(char)
    seen = set()

print count

print list(count.values()).count(len(lines))

There are, of course even better ways to do this.

Accepted Answer