Challenges

Floating Number
Bob has a floating point number N. He wants to set the precision for 2...
Max. Marks: 4
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SwapMaster solves Symmetric Swap
The SwapMaster is known to be the greatest and fastest swapper of all ...
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String Matching
Cody has a sequence of characters N. He likes a sequence if it contain...
Max. Marks: 3
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Leap Year
Steve is playing a quiz game with his brother John. As Steve just lear...
Max. Marks: 6
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Project Teams
There are N students in a class and Teacher want to divide these stude...
Max. Marks: 5
Solved By : 3301
Circle of Numbers
All numbers in NumberLand are standing in a circle for a dancing cerem...
Max. Marks: 6
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Happy String
A happy string is a string in which each character is lexicographicall...
Max. Marks: 4
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Degree Celsius
Tom is a scientist. He uses huge machines for complex calculations. Th...
Max. Marks: 4
Solved By : 3817
Three's Company
This problem requires you to create a output string from input string ...
Max. Marks: 4
Solved By : 2605
Array Sum
You are given an integer array and you have to find the sum of the ele...
Max. Marks: 4
Solved By : 2587
Arithmetic Sequence
Please select a challenge
Problem Statement
In mathematics, an arithmetic progression (AP) or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant. John was writing an Arithmetic sequence with N terms, but while writing he mistakenly made one wrong entry and he is sure that first term is right. Help him to find the wrong term entered by him.

Input
The first line of input contains a single line T, which represents the number of testcases. Then first line of each test case contains an integer N :Total number of terms. Then N space separated integers denoting the sequence.

Output
For each test case. Print the wrongly entered term.

Constraints
1<=T<=100. 4<=N<=1000. 1<=Terms<=1000.

Sample Input
2
5
1 3 5 6 9
4
1 2 3 5

Sample Output

6
5

Dcoded By: Bhanu Nadar

Solved By: 357

Maximum Marks: 6