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I recently came across a question somewhere:
Suppose you have an array of 1001 integers. The integers are in random order, but you know each of the integers is between 1 and 1000 (inclusive). In addition, each number appears only once in the array, except for one number, which occurs twice. Assume that you can access each element of the array only once. Describe an algorithm to find the repeated number. If you used auxiliary storage in your algorithm, can you find an algorithm that does not require it?
What I am interested in to know is the second part, i.e., without using auxiliary storage. Do you have any idea?
637
For an array to contain consecutive integers, The difference between the maximum and minimum element in it should be exactly n-1 . All elements in the array should be distinct (we can check this by inserting the elements in a set or using a visited array).
Just add them all up, and subtract the total you would expect if only 1001 numbers were used from that.
Eg:
Input: 1,2,3,2,4 => 12 Expected: 1,2,3,4 => 10 Input - Expected => 2 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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