{"problem":{"name":"[EC Final 2021] Future Coder","description":{"content":"Prof. Pang builds his famous coding team recently. To pursue a gold medal in ICPC, hundreds of pupils join his team. Unfortunately, one of Prof. Pang's students believes that for any integers $a$ and ","description_type":"Markdown"},"platform":"Luogu","limit":{"time_limit":1000,"memory_limit":1048576},"difficulty":{"LuoguStyle":"P2"},"is_remote":true,"is_sync":true,"sync_url":null,"sign":"LGP9880"},"statements":[{"statement_type":"Markdown","content":"Prof. Pang builds his famous coding team recently. To pursue a gold medal in ICPC, hundreds of pupils join his team. Unfortunately, one of Prof. Pang's students believes that for any integers $a$ and $b$, $a\\times b\\ge a+b$. To disprove this proposition, Prof. Pang writes $n$ numbers $a_1,a_2,\\ldots, a_n$ on a paper and wants you to count how many pairs of numbers $(a_i, a_j)$ ($1\\le i < j\\le n$) satisfies $a_i\\times a_j<a_i+a_j$.\n\n## Input\n\nThe first line contains a single integer $T$ ($1\\le T\\le 10^6$) denoting the number of test cases.\n\nFor each test case, the first line contains a single integer $n$ ($1\\le n\\le 10^6$). The second line contains $n$ integers $a_1, a_2, \\ldots, a_n$ ($-10^9\\le a_i\\le 10^9$).\n\nIt is guaranteed that the sum of $n$ over all test cases will not exceed $10^6$.\n\n## Output\n\nFor each test case, print one line containing the answer.\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"LGP9880","tags":["2021","Special Judge","O2优化","ICPC","EC Final"],"sample_group":[["2\n8\n3 -1 4 1 -5 9 2 -6\n1\n0\n","19\n0\n"]],"created_at":"2026-03-03 11:09:25"}}