LeetCode explained by Dalle, a Korean developer working at a Silicon Valley startup! This is a practical LeetCode problem-solving course that doesn't just provide answer codes, but compares multiple approaches for each problem, analyzes time and space complexity together, and explains why certain solutions are more efficient. First, we write the most intuitive approach and analyze its time/space complexity to identify bottlenecks and improvement points. Then, we explore alternative approaches applying various data structures and algorithmic techniques, comparing the performance differences and pros and cons of each method. Through this, it helps you develop problem-solving skills to design efficient solution strategies on your own when facing new problems.