{"trustable":false,"prependHtml":"\u003cstyle type\u003d\u0027text/css\u0027\u003e\n .input, .output {\n border: 1px solid #888888;\n }\n .output {\n margin-bottom: 1em;\n position: relative;\n top: -1px;\n }\n .output pre, .input pre {\n background-color: #EFEFEF;\n line-height: 1.25em;\n margin: 0;\n padding: 0.25em;\n }\n \u003c/style\u003e\n \u003clink rel\u003d\"stylesheet\" href\u003d\"//codeforces.org/s/96598/css/problem-statement.css\" type\u003d\"text/css\" /\u003e\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 type\u003d\"text/javascript\" async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS_HTML-full\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"MD","content":"给你一个字符串s,切割成 k(k为偶数)个串 p1,p2....pk,使得:\n1. p1,p2,p3...pk 全部拼起来得到 s;\n2. 对于1\u003c\u003di\u003c\u003dk,p[i]\u003dp[k-i+1]。\n\n这样,{p1,p2...pk} 为 s 的一个“对称划分”。\n给定一个偶数长度的字符串 s,求有多少不同的“对称划分”。s 的长度\u003c\u003d1e6。"}},{"title":"","value":{"format":"MD","content":"## Input\nabcdcdab\n\n## Output\n1"}},{"title":"","value":{"format":"MD","content":"## Input\nabbababababbab\n\n## Output\n3"}}]}