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https://github.com/TheAlgorithms/Ruby
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61 lines
No EOL
1 KiB
Ruby
61 lines
No EOL
1 KiB
Ruby
# Challenge name: Single Number
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#
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# Given a non-empty array of integers nums, every element appears twice
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# except for one. Find that single one.
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#
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# Follow up: Could you implement a solution with a linear runtime
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# complexity and without using extra memory?
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#
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# @param {Integer[]} nums
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# @return {Integer}
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#
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# Approach 1: Hash map
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#
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# Time Complexity: O(n)
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#
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def single_number(nums)
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result_hash = {}
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nums.each do |num|
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if result_hash[num]
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result_hash[num] +=1
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else
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result_hash[num] = 1
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end
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end
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result_hash.each do |k, v|
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return k if v == 1
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end
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end
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nums = [2, 2, 1]
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puts(single_number(nums))
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# Output: 1
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nums = [4, 1, 2, 1, 2]
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puts(single_number(nums))
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# Output: 4
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nums = [1]
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puts(single_number(nums))
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# Output: 1
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#
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# Approach 2: Use Ruby .count()
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#
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# Time Complexity: O(n^2)
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#
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def single_number(nums)
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nums.find do |num|
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nums.count(num) == 1
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end
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end
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nums = [2, 2, 1]
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puts(single_number(nums))
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# Output: 1
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nums = [4, 1, 2, 1, 2]
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puts(single_number(nums))
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# Output: 4
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nums = [1]
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puts(single_number(nums))
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# Output: 1 |