http://poj.org/problem?id=3526 https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1284 https://codeforces.com/gym/101415/attachments https://www.acmicpc.net/problem/3904 https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=4143
https://vjudge.net/problem/POJ-3526 https://vjudge.net/problem/Aizu-1284 https://vjudge.net/problem/Gym-101415J https://vjudge.net/problem/Baekjoon-3904 https://vjudge.net/problem/UVA-1397
http://poj.org/problem?id=3523 https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1281 https://www.acmicpc.net/problem/3901 https://codeforces.com/gym/101415/attachments
https://vjudge.net/problem/POJ-3523 https://vjudge.net/problem/Aizu-1281 https://vjudge.net/problem/Baekjoon-3901 https://vjudge.net/problem/Gym-101415G
http://poj.org/problem?id=3180 https://www.luogu.com.cn/problem/P2863
https://vjudge.net/problem/POJ-3180 https://vjudge.net/problem/%E6%B4%9B%E8%B0%B7-P2863 （海外のカートゥーンなど出てくる（？）、牧場で馬が水を飲んでいたりする丸いタンクをストック・タンクというらしい ）