Question #292619
Swap Letters
Anil is given a sentense S.He tries to make this sentence special.A sentence can be made special by swapping the character with the highest frequency with the character having the lowest frequency in the sentence.Help Anil by transforming the sentence into a special Sentence.
Note:
Consider Upper and lower case letters as different.
If there are multiple letters with the same frequency, choose the lower case letter that comes earliest in dictionary order.
a.If letters like x and B have the same frequency consider x.
b.If letters like x and b have the same frequency consider b.
Input
The first line of input is a string.
sample input1
Python is a programming language.
sample output1
Python is e progremming lenguega.
sample input2
CHECK your blood PRESSURE frequently.
sample output2
CHECK ybur olbbd PRESSURE frequently.
Expert's answer
def selectLetter(ch1, ch2):
if 'a' <= ch1 <= 'z' and 'A' <= ch2 <= 'Z':
return ch1
if 'a' <= ch2 <= 'z' and 'A' <= ch1 <= 'Z':
return ch2
if ch1 < ch2:
return ch1
return ch2
def specialSentence(s):
D = {}
for ch in s:
if 'a' <= ch <= 'z' or 'A' <= ch <= 'Z':
D[ch] = D.get(ch, 0) + 1
minFr = len(s)+1
lessFrCh = None
maxFr = 0
moreFrCh = None
for ch in D:
if D[ch] < minFr:
minFr = D[ch]
lessFrCh = ch
elif D[ch] == minFr:
lessFrCh = selectLetter(ch, lessFrCh)
if D[ch] > maxFr:
maxFr = D[ch]
moreFrCh = ch
elif D[ch] == maxFr:
moreFrCh = selectLetter(ch, moreFrCh)
res = ''
for ch in s:
if ch == lessFrCh:
res += moreFrCh
elif ch == moreFrCh:
res += lessFrCh
else:
res += ch
return res
def main():
s = input()
ss = specialSentence(s)
print(ss)
main()
