题目：原题链接（中等）
标签：数组、双指针、滑动窗口
| 解法 | 时间复杂度 | 空间复杂度 | 执行用时 |
|---|---|---|---|
| Ans 1 (Python) | O ( S 1 + S 2 ) O(S1+S2) O(S1+S2) | O ( S 1 ) O(S1) O(S1) | 100ms (41.36%) |
| Ans 2 (Python) | |||
| Ans 3 (Python) |
解法一：
class Solution:
def checkInclusion(self, s1: str, s2: str) -> bool:
need, window = collections.Counter(s1), collections.Counter()
count = 0
i1 = i2 = 0
while i2 < len(s2):
ch2 = s2[i2]
i2 += 1
if ch2 in need:
window[ch2] += 1
if window[ch2] == need[ch2]:
count += 1
while i2 - i1 >= len(s1):
if count == len(need):
return True
ch1 = s2[i1]
i1 += 1
if ch1 in window:
if window[ch1] == need[ch1]:
count -= 1
window[ch1] -= 1
return False
