Short Problem Definition:
Sami’s spaceship crashed on Mars! She sends a series of SOS
messages to Earth for help.
Link
Complexity:
time complexity is O(N)
space complexity is O(1)
Execution:
We know that the message is basically a lot of concatenated SOS strings. There is no magic to this one.
Solution:
S = raw_input().strip()
errors = 0
for i in xrange(len(S)):
if i % 3 == 0 and S[i] != 'S':
errors += 1
if i % 3 == 1 and S[i] != 'O':
errors += 1
if i % 3 == 2 and S[i] != 'S':
errors += 1
print errors