edit README.md

Author: 3bbaas

README.md

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+### What we need to know before starting?
+
+- **Generator**: Program to generate testcases for your problem and test participants solutions.
+- **Validator**: Program to check all testcases is generated in correctly range from constraints.
+- **Checker**: Program to check all participants solution is correctly or not.
+- **Solutions**: We mean here Judge solution and main solution should be 100% correctly to be compared with another solution results.
+- **Polygon-Codeforces Library**: You should install it [testlib.h](https://github.com/MikeMirzayanov/testlib).
+- **Polygon-Codeforces Library Tutorial**: Check here [CF-testlib.h blogs](https://codeforces.com/testlib).
+
+---
+
 ## Problem Creation process
 
 [//]: # (<details>)