Added problem 1

Author: zonedoutdg

Problems/q001.md

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+# PROBLEM STATEMENT :
+
+There are **n people** standing in a circle. They are numbered from **1 to n** in a clockwise order. The circle is **even** (i.e. *n* is even).
+
+Each person is looking at the person standing exactly opposite him in the circle.
+
+You are given three **distinct** integers **a**, **b**, and **c**. It is known that person **a** is looking at person **b**.
+
+Determine the number of the person that person **c** is looking at.  
+If there are **multiple answers**, print **any** of them.  
+If there is **no answer**, print **-1**.
+
+---
+
+## Input
+
+The first line contains a single integer **t**  
+(**1 ≤ t ≤ 10⁴**) — the number of test cases.
+
+Each of the following **t** lines contains three distinct integers **a**, **b**, and **c**  
+(**1 ≤ a, b, c ≤ 10⁸**).
+
+---
+
+## Output
+
+For each test case, print the answer —  
+the number of the person that person **c** is looking at,  
+or **-1** if the answer does not exist.
+
+---
+
+## Example
+
+### Input
+```
+7
+6 2 4
+2 3 1
+2 4 10
+5 3 4
+1 3 2
+2 5 4
+4 3 2
+```
+
+
+### Output
+```
+8
+-1
+-1
+-1
+4
+1
+-1
+```
+The problem statement is given just in case the codeforces server lags.<br>
+Submit your solution in the link given below and send a PR upon receiving AC.
+
+[PROBLEM LINK](https://codeforces.com/problemset/problem/1560/B)
+
+