{"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$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript type\u003d\"text/javascript\" async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS_HTML-full\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cp\u003e给定一个长度为$$$n$$$的整数序列和一个整数$$$k$$$. 你需要在区间$$$[1; 10^9]$$$ (即$$$1 \\le x \\le 10^9$$$) 中寻找一个任意整数解$$$x$$$满足序列中有$$$k$$$个元素小于等于$$$x$$$.\u003c/p\u003e\n\u003cp\u003e注意序列中可能有重复元素.\u003c/p\u003e\n\u003cp\u003e如果无解,输出 \u003cspan class\u003d\"tex-font-style-tt\"\u003e-1\u003c/span\u003e\u003c/p\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cp\u003e第一行输入两个整数$$$n$$$和$$$k$$$ ($$$1 \\le n \\le 2 \\cdot 10^5$$$, $$$0 \\le k \\le n$$$). 第二行包含$$$n$$$个整数组成的序列:$$$a_1, a_2, \\dots, a_n$$$ ($$$1 \\le a_i \\le 10^9$$$) \u003c/p\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cp\u003e输出区间 $$$[1; 10^9]$$$ 中任意一个整数解 $$$x$$$ 满足序列中有$$$k$$$个元素小于等于$$$x$$$.\u003c/p\u003e\n\u003cp\u003e如果无解,输出 \u003cspan class\u003d\"tex-font-style-tt\"\u003e-1\u003c/span\u003e\u003c/p\u003e"}},{"title":"Sample 1","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\u003e7 4\n54 12 47 11 9 6 42\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e12\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}},{"title":"Sample 2","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\u003e5 3\n5 5 5 5 5\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e-1\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}