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Commit b5c8c6a

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added Two Sum - Unique Pairs
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‎Array/TwoSumUniquePairs/README.md

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# Two Sum - Unique Pairs
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[Leetcode Link](https://leetcode.com/discuss/interview-question/372434)
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## Problem:
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Given an int array nums and an int target, find how many unique pairs in the array such that their sum is equal to target. Return the number of pairs.
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## Example:
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```
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Input: nums = [1, 1, 2, 45, 46, 46], target = 47
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Output: 2
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Explanation:
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1 + 46 = 47
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2 + 45 = 47
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```
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```
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Input: nums = [1, 1], target = 2
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Output: 1
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Explanation:
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1 + 1 = 2
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```
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```
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Input: nums = [1, 5, 1, 5], target = 6
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Output: 1
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Explanation:
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[1, 5] and [5, 1] are considered the same.
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```

‎Array/TwoSumUniquePairs/solution.py

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def uniqueTwoSum(nums, target):
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numPairs = 0
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# sort array
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nums.sort()
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# two pointers from left-end and right-end
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left = 0
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right = len(nums)-1
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while left < right:
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# skip the same numbers (finding UNIQUE pairs)
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while left >= 1 and nums[left] == nums[left-1]:
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left += 1
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if left >= len(nums):
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break
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while right < len(nums)-1 and nums[right] == nums[right+1]:
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right -= 1
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if right < 0:
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break
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if left >= right:
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break
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if nums[left] + nums[right] == target:
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numPairs += 1
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left += 1
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right -= 1
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elif nums[left] + nums[right] > target:
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right -= 1
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else:
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left += 1
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return numPairs
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# simple test case
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nums = [1, 1, 2, 3, 4, 4, 43, 45, 45, 46, 46]
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target = 47
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print(uniqueTwoSum(nums, target))
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# all dups
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nums = [1, 1, 1, 1, 1, 1, 1]
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target = 2
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print(uniqueTwoSum(nums, target))
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# no two sum to target
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nums = [2, 3, 6, 2, 3]
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target = 7
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print(uniqueTwoSum(nums, target))
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# unique
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nums = [1, 5, 1, 5]
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target = 6
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print(uniqueTwoSum(nums, target))

‎README.md

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- [Subarray Sum Equals K](Array/SubarraySumEqualsK)
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- [Sum Of Even Numbers After Queries](Array/SumOfEvenNumbersAfterQueries)
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- [Third Maximum Number](Array/ThirdMaximumNumber)
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- [Two Sum - Unique Pairs](Array/TwoSumUniquePairs)
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### [Bit Manipulation](./BitManipulation)
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