LeetCode 392. Is Subsequence
Published in
Mar 14, 2021
題目:
給兩個string s跟t,check if s
is a subsequence of t。(順序不能變)
返回true or false
Example 1:
Input: s = "abc", t = "ahbgdc"
Output: true
Example 2:
Input: s = "axc", t = "ahbgdc"
Output: false
思路:
- 先看s是否存在,如果不存在,那s就會是所有t的subsequence
if not s:
return True - 首先需要知道s長度多少確保可以go through整個s
len_s = len(s) - 接著換go through string t 的每個字母 要對應string s中的字母是否相同
i=0 意思是從s的第一個字母開始比較
for char in t:
if char = s[i]:
i += 1 (有對應到字母則i+1比較下一個字母)
if i == len_s:
意思是已經找到所有s在t裡面的字母,
return True - return False
Coding:
class Solution:
def isSubsequence(self, s: str, t: str) -> bool:
if not s :
return True
len_s = len(s)
i=0
for char in t:
if char == s[i]:
i+=1
if i == len_s:
return True
return False