Hi guys i have been check for my code many many times but i still confuse where is this error come from.... This error appear while build solution...Experts suggest please. And if you don't like this post,do not give negative vote..,just ignore it.It demotivated programmers. My code link is here : https://www.imageupload.net/image/capture3.mY8tQ

The problem statement link : https://codeforces.me/contest/1343/problem/B

Which topics should i know to do better in programming contest?Like data structure,ad-hoc,geometry etc.I am new in programming.Help please

I'm getting runtime error with exit code -1073741571.Help please problem link : https://codeforces.me/problemset/problem/254/A Here is my submission screenshot url : https://www.imageupload.net/image/capture2.dbfwh