Quadruple Sum

Given a sorted array of integers, find all the unique quadruplets which sum up to the given target.

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Note: Each quadruplet must have elements [input[i], input[j], input[k], input[l]], such that i < j < k < l. The ordering of unique quadruplets within the output list does not matter.

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Example:

Input  : {1,2,3,4,5,6,7,8} 
Target : 10
Output : [[1, 2, 3, 4]]