{"problem":{"name":"11. Labyrinth-11","description":{"content":"See the problem statement here: [http://codeforces.com/contest/921/problem/01](//codeforces.com/contest/921/problem/01).","description_type":"Markdown"},"platform":"Codeforces","limit":{"time_limit":8000,"memory_limit":524288},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"CF92111"},"statements":[{"statement_type":"Markdown","content":"See the problem statement here: [http://codeforces.com/contest/921/problem/01](//codeforces.com/contest/921/problem/01).\n\n[samples]","is_translate":false,"language":"English"},{"statement_type":"Markdown","content":"请在此处查看题目描述：http://codeforces.com/contest/921/problem/01.\n\n[samples]","is_translate":true,"language":"Chinese"},{"statement_type":"Markdown","content":"**Definitions**  \nLet $ n \\in \\mathbb{Z}^+ $ be the length of the sequence.  \nLet $ A = (a_1, a_2, \\dots, a_n) $ be a sequence of positive integers.\n\n**Constraints**  \n1. $ 1 \\leq n \\leq 100 $  \n2. $ 1 \\leq a_i \\leq 100 $ for all $ i \\in \\{1, \\dots, n\\} $\n\n**Objective**  \nFind the minimum number of elements to remove from $ A $ such that the remaining subsequence has an alternating sum of zero, i.e., if the remaining elements are $ b_1, b_2, \\dots, b_m $, then:  \n$$\n\\sum_{i=1}^{m} (-1)^{i-1} b_i = 0\n$$","is_translate":false,"language":"Formal"}],"meta":{"iden":"CF92111","tags":[],"sample_group":[],"created_at":"2026-03-03 11:00:39"}}