UCPC UCPC 2021 PS CP solved.ac boj dp segment tree MCMF SNUPC SNUPC 2019 math combinatorics ChAOS 2021 NPC NPC 2021 BAPC 2020 class 6 class 7 mcmf mo's bitfield dp NWERC 2020 ICPC 2018 BOJ BOJ 16360 BOJ 16362 BOJ 16368 BOJ 16357 BOJ 16367 BOJ 16358 BOJ 16363 BOJ 16359 BOJ 16361 BOJ 16366 suffix array euler tour technique geometry ICPCLatin 2019 Latin America Regional flow bipartite matching ICPCJP 2018 Asia Yokohama Regional ICPC ICPC 2021 class 9 kmp lazy propagation greedy two pointer ICPCJP 2020 dfs sweeping ps rust fastio