Difference between subarray, subset & subsequence

Consider an array: {1,2,3,4} Subarray: contiguous sequence in an array i.e. {1,2},{1,2,3} Subsequence: Need not to be contiguous, but maintains order i.e. {1,2,4} Subset: Same as subsequence except it has empty set i.e. {1,3},{} Given an array/sequence of size n, possible Subarray = n*(n+1)/2 Subseqeunce = (2^n) -1 (non-empty subsequences) Subset = 2^n

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