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Given an array of integers, return true if each element in the array appears exactly twice. Solve this without modifying the given array or creating a new array. eachDuplicate([1, 1, 2, 2, 3, 3]) → true eachDuplicate([1, 2, 3, 3, 2, 1]) → true eachDuplicate([3, 1, 4, 1, 3, 5, 4]) → false ...Save, Compile, Run (ctrl-enter)  | 
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Difficulty: 300
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