Closest Sum

Posted: 12 Nov, 2020
Difficulty: Moderate

PROBLEM STATEMENT

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Given an array 'ARR'' of 'N' integers and an integer 'target', your task is to find three integers in 'ARR' such that the sum is closest to the target.

Note
In the case of two closest sums, print the smallest sum.
Input Format
The first line contains an integer 'T' which denotes the number of test cases or queries to be run. Then, the T test cases follow.

The first line of each test case or query contains an integer 'N' representing the size of the array.

The second line contains 'N' single space-separated integers, representing the elements in the array.

The third line contains the value of the target.
Output Format
For each test case, print the sum of triplets closest to the target.

Print the output of each test case in a new line.
Note
You do not need to print anything, it has already been taken care of. Just implement the given function.
Constraints
1 <= T <= 10 
3 <= N <= 100 
-10^5 <= Arr[i] <= 10^5
-3 * 10^5 <= target <= 3 * 10^5

where Arr[i] refers to the elements of the array.

Time Limit: 1 sec
Approach 1

The approach is to explore all the subsets of size 3 and keep a track of the difference between the target value and the sum of this subset. Then return the sum which is the closest to the target.

 

  • Create three nested loops with counter i, j and k respectively.
  • The first loop will run from 0 to N-1, the second loop will run from i+1 to N-1 and the third loop will run from j+1 to N-1.
  • Check if the absolute difference of the sum of ith, jth and kth element and the value of the target is less than the absolute difference of the current value of closest sum and the value of the target. Update the closest sum if required.
  • Print the closest sum.
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