# algorithm

Question

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You are given an array of n numbers and a number K.

You have to find three elements from the arra whose sum is equal to K.

Find the complexity of the algorithm using Brute Force and optimal approach.

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Brute force:

Use three for loops and check for each combination of three elements. $O(n^3)$

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Otherwise,

• Sort array $n \log n$
• Use greedy approach by fixing two elements and scanning using third element. 
• Overall n square complexity

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also here : http://www.geeksforgeeks.org/find-a-triplet-that-sum-to-a-given-value/