{"trustable":true,"prependHtml":"\u003cscript\u003e window.katexOptions \u003d { disable: true }; \u003c/script\u003e\n\u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {\n inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027], [\u0027$\u0027,\u0027$\u0027]],\n displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027], [\u0027$$\u0027,\u0027$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\" type\u003d\"text/javascript\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"panel_content\"\u003eHotaru Ichijou recently is addicated to math problems. Now she is playing with N-sequence.\u003cbr\u003eLet\u0027s define N-sequence, which is composed with three parts and satisfied with the following condition:\u003cbr\u003e1. the first part is the same as the thrid part,\u003cbr\u003e2. the first part and the second part are symmetrical.\u003cbr\u003efor example, the sequence 2,3,4,4,3,2,2,3,4 is a N-sequence, which the first part 2,3,4 is the same as the thrid part 2,3,4, the first part 2,3,4 and the second part 4,3,2 are symmetrical.\u003cbr\u003e\u003cbr\u003eGive you n positive intergers, your task is to find the largest continuous sub-sequence, which is N-sequence.\u003cbr\u003e\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"There are multiple test cases. The first line of input contains an integer T(T\u0026lt;\u003d20), indicating the number of test cases. \u003cbr\u003e\u003cbr\u003eFor each test case:\u003cbr\u003e\u003cbr\u003ethe first line of input contains a positive integer N(1\u0026lt;\u003dN\u0026lt;\u003d100000), the length of a given sequence\u003cbr\u003e\u003cbr\u003ethe second line includes N non-negative integers ,each interger is no larger than $10^9$ , descripting a sequence.\u003cbr\u003e"}},{"title":"Output","value":{"format":"HTML","content":"Each case contains only one line. Each line should start with “Case #i: ”,with i implying the case number, followed by a integer, the largest length of N-sequence.\u003cbr\u003e\u003cbr\u003eWe guarantee that the sum of all answers is less than 800000.\u003cbr\u003e"}},{"title":"Sample","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e1\r\n10\r\n2 3 4 4 3 2 2 3 4 4\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eCase #1: 9\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}