{"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":"瑞瑞最近迷上了字符串,因此决定出一个字符串的题。\n\n给定两个正整数 N、K,考虑所有由 N - 2 个 a 和 2 个 b 组成的字符串,要求输出其中字典序第 K 小的。\n\n例如当 N \u003d 5 时,共有如下 10 种组成方式:\n1. aaabb\n2. aabab\n3. aabba\n4. abaab\n5. ababa\n6. abbaa\n7. baaab\n8. baaba\n9. babaa\n10. bbaaa"}},{"title":"Input","value":{"format":"MD","content":"多组数据,第一行给定 T,表示数据组数。(1 ≤ T ≤ 1e4)\n\n对于每组数据,给出两个正整数 N、K。(3 ≤ N ≤ 1e5, 1 ≤ K ≤ min(2e9, N * (N-1) / 2 ))\n\nN 的总和不会超过 1e5。"}},{"title":"Output","value":{"format":"MD","content":"对于每组数据,输出长度为 N 的字典序第 K 小的字符串。"}},{"title":"Example","value":{"format":"MD","content":"\u003cdiv class\u003d\"sample-test\"\u003e \n \u003cdiv class\u003d\"input\"\u003e \n \u003cdiv class\u003d\"title\"\u003e\n Input\n \u003c/div\u003e \n \u003cpre\u003e7\n5 1\n5 2\n5 8\n5 10\n3 1\n3 2\n20 100\n\u003c/pre\u003e\n \u003c/div\u003e \n \u003cdiv class\u003d\"output\"\u003e \n \u003cdiv class\u003d\"title\"\u003e\n Output\n \u003c/div\u003e \n \u003cpre\u003eaaabb\naabab\nbaaba\nbbaaa\nabb\nbab\naaaaabaaaaabaaaaaaaa\n\u003c/pre\u003e\n \u003c/div\u003e\n\u003c/div\u003e"}}]}