{"trustable":false,"prependHtml":"\u003cstyle type\u003d\"text/css\"\u003e\n section pre {\n display: block;\n padding: 9.5px;\n margin: 0 0 10px;\n font-size: 13px;\n line-height: 1.42857143;\n word-break: break-all;\n word-wrap: break-word;\n color: #333;\n background: rgba(255, 255, 255, 0.5);\n border: 1px solid #ccc;\n border-radius: 6px;\n }\n\u003c/style\u003e\n\u003cscript\u003e\n window.katexOptions \u003d {\n delimiters: [\n {left: \u0027\\\\(\u0027, right: \u0027\\\\)\u0027, display: false},\n {left: \u0027\\\\[\u0027, right: \u0027\\\\]\u0027, display: true}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"题目描述","value":{"format":"MD","content":"给出一张简单连通无向图,包含 `N` 个点和 `M` 条边。点的编号为 `1` 至 `N`,边的编号为 `1` 至 `M`。\n\n第 `i` 条边双向连接了点 `u_i` 和点 `v_i`。\n\n判断是否能找出三条回路使得每条边被使用恰好一次。\n\n回路是一条首尾相接的路径,允许重复经过相同的点但不允许重复经过相同的边。"}},{"title":"数据范围","value":{"format":"MD","content":"`1≤N,M≤1e5`"}},{"title":"输入格式","value":{"format":"MD","content":"长这样:\n```\nN M\nu_1 v_1\n...\nu_m v_m\n```"}},{"title":"输出格式","value":{"format":"MD","content":"\u003csection\u003e \n \u003cp\u003eIf three circuits can be formed using each of the edges exactly once, print \u003ccode\u003eYes\u003c/code\u003e; if they cannot, print \u003ccode\u003eNo\u003c/code\u003e.\u003c/p\u003e \n\u003c/section\u003e"}},{"title":"样例1","value":{"format":"MD","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 9\n1 2\n1 3\n2 3\n1 4\n1 5\n4 5\n1 6\n1 7\n6 7\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eYes\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003csection\u003e \n \u003cul\u003e \n \u003cli\u003eThree circuits can be formed using each of the edges exactly once, as follows: \n \u003cdiv style\u003d\"text-align: center;\"\u003e \n \u003cimg alt\u003d\"b8c8e2245d45a31cf39749b0a49fc2bd.png\" src\u003d\"CDN_BASE_URL/65d1a033185fb97b45c99a1248950ed5?v\u003d1652658672\"\u003e \n \u003c/div\u003e\u003c/li\u003e \n \u003c/ul\u003e \n\u003c/section\u003e"}},{"title":"样例2","value":{"format":"MD","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\u003e3 3\n1 2\n2 3\n3 1\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eNo\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003csection\u003e \n \u003cul\u003e \n \u003cli\u003eThree circuits are needed.\u003c/li\u003e \n \u003c/ul\u003e \n\u003c/section\u003e"}},{"title":"样例3","value":{"format":"MD","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\u003e18 27\n17 7\n12 15\n18 17\n13 18\n13 6\n5 7\n7 1\n14 5\n15 11\n7 6\n1 9\n5 4\n18 16\n4 6\n7 2\n7 11\n6 3\n12 14\n5 2\n10 5\n7 8\n10 15\n3 15\n9 8\n7 15\n5 16\n18 15\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eYes\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e"}}]}