Easy•Array · Sorting · Hash Set
LeetCode #217Contains Duplicate
Given an integer array, return true when any value appears at least twice; otherwise return false.
In very simple words
Ask one question: Did I see any number more than once?
[1, 2, 3, 1]true — 1 appears twice
[1, 2, 3, 4]false — every value is unique
Have you solved it before?
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Solve It With Small Hints
Read one hint, pause, and try again before opening the next.
Step 1
Say the question in your own words
Return true if any number appears more than once. Return false if every number appears only once.
[1, 2, 3, 1] contains another 1, so the answer is true.
Complete Answer
Both approaches, dry runs, Go code, complexity, and mistakes.
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