{"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$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\" type\u003d\"text/javascript\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"panel_content\"\u003eLink has a function $f(x)$, where $x$ and $f(x)$ are both integers in $[1,n]$.\u003cbr\u003e\u003cbr\u003eLet $f_n(x)\u003df(f_{n-1}(x))$ and $f_1(x) \u003d f(x)$, he define the power of a number $x$ as:\u003cbr\u003e$$g(x) \u003d \\lim \\limits_{n \\to + \\infty} \\frac{1}{n} \\sum_{i\u003d1}^{n} f_i(x)$$ \u003cbr\u003e\u003cbr\u003eHe wants to know whether $x$ has the same power for all $x \\in [1,n]$.\u003cbr\u003e\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"The input consists of multiple test cases. \u003cbr\u003e\u003cbr\u003eThe first line contains an integer $T$ ($1 \\leq T \\leq 100$) -- the number of test cases.\u003cbr\u003e\u003cbr\u003eFor each test case:\u003cbr\u003e\u003cbr\u003eIn the first line, there is an integer $n$ ($1 \\leq n \\leq 10^5$).\u003cbr\u003e\u003cbr\u003eIn the second line, there are $n$ integers, the $i$-th integer shows the value of $f(i)$ ($1 \\leq f(i) \\leq n$).\u003cbr\u003e\u003cbr\u003eIt is guaranteed that the sum of $n$ over all test cases will not exceed $10^6$.\u003cbr\u003e"}},{"title":"Output","value":{"format":"HTML","content":"For each test case, output \u0027YES\u0027 if all $x$ have the same power. Otherwise, output \u0027NO\u0027.\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\u003e2\r\n2\r\n1 2\r\n2\r\n1 1\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eNO\r\nYES\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}