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https://github.com/TheAlgorithms/Ruby
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41 lines
818 B
Ruby
41 lines
818 B
Ruby
# Challenge name: Number of good pairs
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#
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# Given an array of integers nums.
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# A pair (i,j) is called good if nums[i] == nums[j] and i < j.
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# Return the number of good pairs.
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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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#
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# Approach 1: Brute Force
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#
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# Time Complexity: O(n^2)
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#
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def num_identical_pairs(nums)
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count = 0
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nums.each_with_index do |num, i|
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target = num
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nums.each_with_index do |num, j|
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next if i >= j
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count += 1 if num == target
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end
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end
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count
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end
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nums = [1, 2, 3, 1, 1, 3]
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puts(num_identical_pairs(nums))
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# Output: 4
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# Explanation: There are 4 good pairs (0,3), (0,4), (3,4), (2,5) 0-indexed.
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nums = [1, 1, 1, 1]
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puts(num_identical_pairs(nums))
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# Output: 6
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# Explanation: Each pair in the array are good.
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nums = [1, 2, 3]
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puts(num_identical_pairs(nums))
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# Output: 0
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