{"trustable":false,"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":"\u003cscript type\u003d\u0027text/x-mathjax-config\u0027\u003eMathJax.Hub.Config({tex2jax: { inlineMath: [[\u0027$\u0027,\u0027$\u0027]] } }); \u003c/script\u003e\n\u003cscript type\u003d\u0027text/javascript\u0027 src\u003d\u0027https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\u0027\u003e\u003c/script\u003e\n\u003cscript type\u003d\u0027text/javascript\u0027\u003esetTimeout(function(){MathJax.Hub.Queue([\u0027Typeset\u0027, MathJax.Hub, \u0027left_view\u0027]);}, 2000);\u003c/script\u003e\n\u003cdiv class\u003d\"panel_content\"\u003e\n Hotaru Ichijou recently is addicated to math problems. Now she is playing with N-sequence. \n \u003cbr\u003eLet\u0027s define N-sequence, which is composed with three parts and satisfied with the following condition: \n \u003cbr\u003e1. the first part is the same as the thrid part, \n \u003cbr\u003e2. the first part and the second part are symmetrical. \n \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. \n \u003cbr\u003e \n \u003cbr\u003eGive you n positive intergers, your task is to find the largest continuous sub-sequence, which is N-sequence. \n \u003cbr\u003e \n\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. \n\u003cbr\u003e \n\u003cbr\u003eFor each test case: \n\u003cbr\u003e \n\u003cbr\u003ethe first line of input contains a positive integer N(1\u0026lt;\u003dN\u0026lt;\u003d100000), the length of a given sequence \n\u003cbr\u003e \n\u003cbr\u003ethe second line includes N non-negative integers ,each interger is no larger than $10^9$ , descripting a sequence. \n\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. \n\u003cbr\u003e \n\u003cbr\u003eWe guarantee that the sum of all answers is less than 800000. \n\u003cbr\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre\u003e1\n10\n2 3 4 4 3 2 2 3 4 4\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre\u003eCase #1: 9\u003c/pre\u003e"}}]}