Here is my code submitted to OI/ACM online judge.
Now it included my code on:
	POJ(poj.org) - Peking University
	Ural(acm.timus.ru) - Ural State University
	BZOJ(www.lydsy.com) - Hengyang No.8 Middle School
	RQNOJ(www.rqnoj.cn) - Renqing Net
	XMUOJ(acm.xmu.edu.cn) - Xiamen University 
	Tsinsen(tsinsen.com) - Tsinsen Online Automatic Judge System
	ZOJ(acm.zju.edu.cn) - Zhejiang University Online Judge
	UVa(uva.onlinejudge.org) - Online judge of Universidad de Valladolid
	LA(livearchive.onlinejudge.org) - ACM/ICPC Live Archive
	HDU(acm.hdu.edu.cn) - Hangzhou Dianzi University Online Judge
	WikiOI(wikioi.com) - Wikioi Judge System
	HOJ(acm.hit.edu.cn) - HIT ACM/ICPC Group Online Judge
	SPOJ(www.spoj.com) - Sphere Online Judge
	Codeforces(codeforces.com) 
All the code is published in public domain. So you can use them in the way you like.