LeetCode 387 | First Unique Character in a String | Python Counting and First Pass | AlgoYogi
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We solve LeetCode 387: First Unique Character in a String using Python with a simple two-pass approach.
Idea: count frequency of each character, then scan once more to find the first index whose count is exactly 1. If none exists, return minus one.
👉 Problem Link: https://leetcode.com/problems/first-u...
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⏱ Timestamps
0:00 Introduction
0:20 Problem Statement
0:30 Counting Approach
5:00 Python Code Walkthrough
6:30 Time and Space Complexity
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💡 Why Watch?
Clean O(n) time, O(1) extra space for fixed alphabets
Works great with Python Counter or an array of size 26
Interview staple for frequency counting and index scanning
#LeetCode #FirstUniqueCharacter #Python #AlgoYogi #HashMap #Counting