{"problem":{"name":"03. Labyrinth-3","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":"CF92103"},"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 $ t \\in \\mathbb{Z} $ be the number of test cases.  \nLet $ T = \\{(n_k, a_k) \\mid k \\in \\{1, \\dots, t\\}\\} $ be the set of test cases, where for each $ k $:  \n- $ n_k \\in \\mathbb{Z} $ is the length of the sequence.  \n- $ a_k = (a_{k,1}, a_{k,2}, \\dots, a_{k,n_k}) $ is a sequence of integers.  \n\n**Constraints**  \n1. $ 1 \\le t \\le 1000 $  \n2. For each $ k \\in \\{1, \\dots, t\\} $:  \n   - $ 1 \\le n_k \\le 50 $  \n   - $ 1 \\le a_{k,i} \\le 100 $ for all $ i \\in \\{1, \\dots, n_k\\} $  \n\n**Objective**  \nFor each test case $ k $, compute the alternating sum:  \n$$\nS_k = \\sum_{i=1}^{n_k} (-1)^{i-1} a_{k,i}\n$$","is_translate":false,"language":"Formal"}],"meta":{"iden":"CF92103","tags":[],"sample_group":[],"created_at":"2026-03-03 11:00:39"}}