프로그래머스 programmers Simulation Samsung BFS DP Brute Force DFS sort Stack/Que Greedy Kakao hash multi-sort 순열/조합 Kruskal deque 2018 기하 heap 정렬 Line Sweaping heapq 2017 점화식 binary search Olympiad Recursion 2020 itertools combination stack SET sorting Data Structure copy math 알고리즘