710 - Python LeetCode

【Leetcode】python - [387] First Unique Character in a String 個人解法筆記 (內含範例程式碼)

題目出處

387. First Unique Character in a String

難度

easy

題目分類

Hash Table, String, Queue, Counting

個人範例程式碼

class Solution:
    def firstUniqChar(self, s: str) -> int:
        worddict = Counter(s)
        for idx, ele in enumerate(s):
            if worddict[ele] >= 2: # has duplicate
                pass
            else:  # no duplicate
                return idx

        return -1

Time Complexity

O(n)

Space Complexity

x

算法說明

透過 Counter 快速完成計算數量，
只要 Counter 計算出數量大於 2 的結果，
直接回傳最早的答案。

corner case 特殊情況處理

x

Boundary conditions/ Edge conditions 邊際情況處理

沒有答案時，要回傳 -1

Reference