题目
Given a string s and a non-empty string p, find all the start indices of p’s anagrams in s.
Strings consists of lowercase English letters only and the length of both strings s and p will not be larger than 20,100.
The order of output does not matter.
解题思路
用sliding window扫描s，把字符串放到一个计数器中，每次更新这个计数器并和p的计数器比较，如果相同就是一个答案
代码
class Solution:
def findAnagrams(self, s: str, p: str) -> List[int]:
def f(c):
return ord(c) - 97
ct_p, ct_s = [0] * 26, [0] * 26
for c in p:
ct_p[f(c)] += 1
l = len(p)
for c in s[:l - 1]:
ct_s[f(c)] += 1
res = []
for i, c in enumerate(s[l - 1:]):
ct_s[f(c)] += 1
if ct_s == ct_p:
res.append(i)
ct_s[f(s[i])] -= 1
return res
