{"problem":{"name":"[ICPC 2022 Jinan R] Stack Sort","description":{"content":"You are given a permutation with $n$ numbers, $a_1, a_2, \\dots, a_n (1\\leq a_i\\leq n, a_i\\neq a_j\\textrm{ when }i\\neq j)$.  You want to sort these numbers using $m$ stacks. Specifically, you should c","description_type":"Markdown"},"platform":"Luogu","limit":{"time_limit":1000,"memory_limit":524288},"difficulty":{"LuoguStyle":"P2"},"is_remote":true,"is_sync":true,"sync_url":null,"sign":"LGP9677"},"statements":[{"statement_type":"Markdown","content":"You are given a permutation with $n$ numbers, $a_1, a_2, \\dots, a_n (1\\leq a_i\\leq n, a_i\\neq a_j\\textrm{ when }i\\neq j)$. \n\nYou want to sort these numbers using $m$ stacks. Specifically, you should complete the following task: \n\nInitially, all stacks are empty. You need to push each number $a_i$ to the top of one of the $m$ stacks one by one, in the order of $a_1,a_2,\\ldots, a_n$. $\\textbf{After pushing all numbers in the stacks}$, you pop all the elements from the stacks in a clever order so that the first number you pop is $1$, the second number you pop is $2$, and so on. **If you pop an element from a stack $S$, you cannot pop any element from the other stacks until $S$ becomes empty.**\n\nWhat is the minimum possible $m$ to complete the task?\n\n## Input\n\nThe first line contains one integer $T~(1\\le T \\le 10^5)$, the number of test cases.\n\nFor each test case, the first line contains one positive integer $n~(1\\le n \\le 5 \\times 10^5)$. The next line contains $n$ integers $a_1,\\ldots, a_n~(1 \\le a_i\\le n)$ denoting the permutation. It is guaranteed that $a_1,\\ldots, a_n$ form a permutation, i.e. $a_i\\neq a_j$ for $i \\neq j$. \n\nIt is guaranteed that the sum of $n$ over all test cases is no more than $5\\times 10^5$.\n\n## Output\n\nFor each test case, output the minimum possible $m$ in one line.\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"LGP9677","tags":["2022","O2优化","ICPC","济南"],"sample_group":[["3\n3\n1 2 3\n3\n3 2 1\n5\n1 4 2 5 3\n","3\n1\n4"]],"created_at":"2026-03-03 11:09:25"}}