algorithm-in-python/codes/manacher.py
2018-07-08 16:41:55 +08:00

26 lines
759 B
Python

class Solution:
def longestPalindrome(self, s):
"""
:type s: str
:rtype: str
"""
n = len(s)
s2='$#'+'#'.join(s)+'#@'
ct =[0]*(2*n+4)
mid=1
for cur in range(1,2*n+2):
if cur<mid+ct[mid]:
ct[cur] = min(ct[2*mid-cur],mid+ct[mid]-cur)
else:
ct[cur]=1
while s2[cur-ct[cur]]==s2[cur+ct[cur]]:
ct[cur]+=1
if cur+ct[cur] > mid+ct[mid]:mid = cur
mx = max(ct)
idxs = [i for i,j in enumerate(ct) if j == mx]
p = idxs[0]
for i in idxs:
if s2[i]=='#':p = i
rst =s2[p-mx+1:p+mx].replace('#','')
return rst