{"id":138,"date":"2021-06-18T11:16:04","date_gmt":"2021-06-18T11:16:04","guid":{"rendered":"http:\/\/cirno.fun\/?p=138"},"modified":"2021-06-18T11:16:04","modified_gmt":"2021-06-18T11:16:04","slug":"%e9%a2%98%e8%a7%a3-cf191c-%e3%80%90fools-and-roads%e3%80%91","status":"publish","type":"post","link":"https:\/\/blog.sssn.tech\/?p=138","title":{"rendered":"\u9898\u89e3 CF191C \u3010Fools and Roads\u3011"},"content":{"rendered":"\n<p>\u53bb\u770b\u9898\u89e3\u5927\u4f6c\u6253\u7684\u770b\u4e0d\u61c2&#8230;\u53ea\u597d\u81ea\u5df1\u52aa\u529b\uff08<del>\u8fde\u8499\u5e26\u6284<\/del>\uff09\u5199\u4e86\u597d\u4e45\u7ec8\u4e8e\u8fc7\u4e86<\/p>\n\n\n\n<p>\u7adf\u7136\u6ca1\u4eba\u53d1\u6811\u5256\uff1f\uff08<del>\u5bb3\u6211\u8c03\u534a\u5929<\/del>\uff09\u7ed3\u5408\u6211\u81ea\u5df1\u770b\u4e0d\u61c2\u9898\u89e3\u7684\u7ecf\u9a8c\uff0c\u6211\u5c3d\u91cf\u5199\u6e05\u695a\u4e9b\uff0c\u987a\u4fbf\u4ecb\u7ecd\u51e0\u4e2a\u8c03\u9519\u7684\u5c0f\u6280\u5de7hhh<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u6811\u94fe\u5256\u5206\u7684\u601d\u60f3\uff1f<\/h4>\n\n\n\n<p>\u6811\u5256\uff0c\u7b80\u5355\u6765\u8bf4\u5c31\u662f\u5c06\u4e00\u68f5\u6811\u5206\u6210<strong>\u7531\u8f7b\u8fb9\u8fde\u6210\u90fd\u91cd\u94fe<\/strong>\uff0c\u4ece\u800c\u4f7f\u5f97\u95ee\u9898\u5927\u5927\u7b80\u5316<\/p>\n\n\n\n<p>\u6211\u4eec\u5047\u8bbe\u6bcf\u4e00\u4e2a\u8282\u70b9\u91cd\u91cf\u662f1\uff0c\u90a3\u4e48\u5bf9\u4e8e\u4efb\u610f\u4e00\u4e2a\u8282\u70b9\uff0c\u4ed6\u7684\u5b50\u6811\u4e2d\u66f4\u91cd\u7684\u90a3\u4e2a\uff0c\u6211\u4eec\u79f0\u4e4b\u4e3a<strong>\u91cd\u5b69\u5b50<\/strong>\uff0c\u5176\u4ed6\u90fd\u79f0\u4e4b\u4e3a<strong>\u8f7b\u5b69\u5b50<\/strong>\u3002\u6211\u4eec\u77e5\u9053\uff0c\u6bcf\u4e00\u4e2a\u8282\u70b9\u90fd\u4f1a\u6709\u4e00\u4e2a\u91cd\u5b69\u5b50\uff0c\u90a3\u4e48\u8fd9\u4e00\u4e32\u91cd\u5b69\u5b50\u94fe\u6211\u4eec\u79f0\u4e4b\u4e3a<strong>\u91cd\u94fe<\/strong>\uff0c\u53cd\u4e4b\u5462\uff0c\u8fde\u63a5\u8f7b\u5b69\u5b50\u7684\u8fb9\u79f0\u4e4b\u4e3a<strong>\u8f7b\u8fb9<\/strong><\/p>\n\n\n\n<p>\u81ea\u5df1\u968f\u4fbf\u627e\u4e9b\u6811\u6765\u753b\u4e00\u753b\uff0c<del>\u6613\u8bc1<\/del>\u6bcf\u4e00\u68f5\u6811\u90fd\u53ef\u4ee5\u5206\u4e3a\u82e5\u5e72\u6761\u91cd\u94fe\uff0c\u91cd\u94fe\u4e0e\u91cd\u94fe\u95f4\u7531\u8f7b\u8fb9\u94fe\u63a5<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u9996\u5148\u662f\u6bcf\u4e2a\u6570\u7ec4\u7684\u542b\u4e49<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp line-numbers\">int sz[N],hs[N],f[N],tp[N],dep[N];<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\"><li>sz\u662f\u4ee5\u6bcf\u4e2a\u8282\u70b9\u4e3a\u6839\u7684\u5b50\u6811\u7684\u91cd\u91cf<\/li><li>hs\u662f\u6bcf\u4e2a\u8282\u70b9\u7684\u91cd\u5b69\u5b50<\/li><li>f\u662f\u6bcf\u4e2a\u8282\u70b9\u7684\u7236\u4eb2<\/li><li>tp\u662f\u6bcf\u4e2a\u8282\u70b9\u6240\u5904\u7684\u91cd\u94fe\u7684\u9876<\/li><li>dep\u662f\u6bcf\u4e2a\u8282\u70b9\u5728\u6811\u4e2d\u7684\u6df1\u5ea6<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">\u8fd9\u662f\u6811\u5256\u7684\u90e8\u5206<\/h2>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp line-numbers\">int sz[N],hs[N],f[N],tp[N],dep[N];\nvoid dfs1(int x,int fa){\n     dep[x]=dep[fa]+1;\n     sz[x]=1;\n     f[x]=fa;\n     hs[x]=0;\n     for(int i=head[x];i;i=nxt[i]){\n         int y=G[i];\n         if(y==fa)   continue;\n         dfs1(y,x);\n         sz[x]+=sz[y];\n         if(sz[y]>sz[hs[x]])\n             hs[x]=y;\n     }\n}\nvoid dfs2(int x,int t){\n     tp[x]=t;\n     if(hs[x])\n         dfs2(hs[x],t);\n     for(int i=head[x];i;i=nxt[i]){\n         int y=G[i];\n         if(y==f[x] || y==hs[x]) continue;\n         dfs2(y,y);\n     }\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">\u7528\u6811\u5256\u6c42LCA\u7684\u601d\u60f3\u662f\uff1a<\/h4>\n\n\n\n<ul class=\"wp-block-list\"><li>\u5bf9\u4e8e\u4e24\u4e2a\u70b9\uff0c\u5982\u679c\u4e0d\u5904\u4e8e\u540c\u4e00\u6761\u91cd\u94fe\uff0c\u5c31\u50cf\u4e0a\u8df3\u51fa\u5f53\u524d\u91cd\u94fe\u76f4\u5230\u5904\u4e8e\u540c\u4e00\u6761\uff0c\u90a3\u4e48\u6b64\u65f6\u4ed6\u4eec\u5fc5\u5b9a\u4e00\u4e2a\u9ad8\u4e00\u4e2a\u4f4e<\/li><\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp line-numbers\">inline int LCA(int x,int y){\n     while(tp[x]!=tp[y]){\n         if(dep[tp[x]]>=dep[tp[y]])\n             x=f[tp[x]];\n         else    y=f[tp[y]];         \/\/\u7279\u522b\u6ce8\u610f\uff0c\u5fc5\u987b\u8df3\u51fa\u91cd\u94fe\uff0c\u4e5f\u5c31\u662f\u8df3\u5230\u9876\u7684\u7236\u4eb2\u4e0a\n     }\n     return dep[x]>dep[y]?y:x;\n}<\/code><\/pre>\n\n\n\n<p>\u8fd9\u9053\u9898\u5df2\u7ecf\u6709\u5927\u4f6c\u66f0\u8fc7\uff0c\u5dee\u5206\u505a\u6cd5\u662f<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp line-numbers\">++s[x],++s[y],s[LCA(x,y)]-=2;<\/code><\/pre>\n\n\n\n<p>\u90a3\u4e48\u6211\u4eec\u5728\u4e00\u4e2adfs\u4e2d\u5c06\u8fd9\u4e2a\u5f71\u54cd\u65bd\u52a0\u5230\u6574\u4e2a\u8def\u5f84\u4e0a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp line-numbers\">int s[N],ans[N],id[N];\nvoid dfs3(int x){\n     for(int i=head[x];i;i=nxt[i]){\n         int y=G[i];\n         if(y==f[x]) continue;\n         dfs3(y);\n         s[x]+=s[y];\n     }\n     ans[id[x]]=s[x];\n }<\/code><\/pre>\n\n\n\n<p>\u611f\u89c9\u8fd9\u4e2a\u505a\u6cd5\u8fd8\u4e0d\u9519\uff0c\u6700\u6162\u4e5f\u4e0d\u8fc7300ms<\/p>\n\n\n\n<p>\u5b8c\u6574\u5185\u5bb9\u8d34\u4e0a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp line-numbers\">#include&lt;iostream>\n#include&lt;cstring>\n#include&lt;algorithm>\n#include&lt;cmath>\n#include&lt;cstdio>\nusing namespace std;\nconst int N=210000,M=N&lt;&lt;1;\/\/\u8bf7\u6ce8\u610f2\u500d...\nstruct node{\n     int x,y;\n     node(int x=0,int y=0):x(x),y(y){}\n}; node edge[N];\/\/\u5355\u9879\u4e0d\u5f00\u4e8c\u500d\nint G[M],head[N],nxt[M],e_cnt=0;\ninline void add(int x,int y){\n     \/\/\u524d\u5411\u661f\n      G[++e_cnt]=y;\n     nxt[e_cnt]=head[x];head[x]=e_cnt;\n }\nint sz[N],hs[N],f[N],tp[N],dep[N]; \/\/\u6211\u731c\u4f60\u4eec\u8bb0\u4e0d\u4f4f\u6570\u7ec4\u7684\u542b\u4e49\uff0c\u5f80\u524d\u7ffb\u7ffb\u5427\nvoid dfs1(int x,int fa){\n     dep[x]=dep[fa]+1;\n     sz[x]=1;\n     f[x]=fa;\n     hs[x]=0;\n     for(int i=head[x];i;i=nxt[i]){\n         int y=G[i];\n         if(y==fa)   continue;\n         dfs1(y,x);\n         sz[x]+=sz[y];\n         if(sz[y]>sz[hs[x]])\n             hs[x]=y;\n     }\n}\nvoid dfs2(int x,int t){\n     tp[x]=t;\n     if(hs[x])\n         dfs2(hs[x],t);\n     for(int i=head[x];i;i=nxt[i]){\n         int y=G[i];\n         if(y==f[x] || y==hs[x]) continue;\n         dfs2(y,y);\n     }\n}\ninline int LCA(int x,int y){\n     while(tp[x]!=tp[y]){\n         if(dep[tp[x]]>=dep[tp[y]])\n             x=f[tp[x]];\n         else    y=f[tp[y]];\n     }\n     return dep[x]>dep[y]?y:x;\n }\nint s[N],ans[N],id[N];\nvoid dfs3(int x){\n     for(int i=head[x];i;i=nxt[i]){\n         int y=G[i];\n         if(y==f[x]) continue;\n         dfs3(y);\n         s[x]+=s[y];\n    }\n    ans[id[x]]=s[x];\n }\nint main(){\n     ios::sync_with_stdio(0);     \/\/\u5173\u95ed\u540c\u6b65\n     int n,k;\/\/n\u4e2a\u70b9\u548ck\u6b21\u95ee\u8be2\n     cin>>n;\n     for(int i=1;i&lt;n;++i){\n         int x,y;\n         cin>>x>>y;\n         edge[i]=node(x,y);\n         add(x,y);   add(y,x);\n     }\n     dfs1(1,0);\n     dfs2(1,1);\n     \/\/\u8fd9\u4e2a\u9898\u8981\u6309\u7167\u8fb9\u7684\u987a\u5e8f\u8f93\u51fa\uff0c\u5f88\u70e6\n     \/\/\u6211\u4eec\u5c06\u8fb9\u7684\u6743\u503c\u65bd\u52a0\u5230\u6df1\u5ea6\u8f83\u5927\u7684\u90a3\u4e2a\u70b9\u4e0a\n      for(int i=1;i&lt;n;++i)\n         if(dep[edge[i].x]>dep[edge[i].y])\n           id[edge[i].x]=i;\n         else\n           id[edge[i].y]=i;\n     cin>>k;\n     for(int i=1;i&lt;=k;++i){\n         int x,y;\n         cin>>x>>y;\n         ++s[x],++s[y],s[LCA(x,y)]-=2;\n         \/\/cout&lt;&lt;\"lca=\"&lt;&lt;LCA(x,y)&lt;&lt;endl;\n         \/\/\u8fd9\u91cc\u662f\u4e2adebug\u7684\u597d\u5730\u65b9\uff0c\u5bf9\u4e8e\u672c\u9898\u6765\u8bf4\u5dee\u5206\u96be\u5ea6\u4e0d\u5927\uff0c\u800clca\u76f4\u63a5\u662f\u6a21\u677f       \/\/\u5728\u8fd9\u91cc\u68c0\u67e5lca\u7ed3\u679c\u53ef\u4ee5\u8fc5\u901f\u786e\u5b9a\u51fa\u9519\u4f4d\u7f6e\n      }\n     dfs3(1);\/\/\u5904\u7406\u6743\u503c\uff0c\u5dee\u5206\n     for(int i=1;i&lt;n;++i)\n         \/\/\u8f93\u7b54\u6848\u8dd1\u8def\n          cout&lt;&lt;ans[i]&lt;&lt;' ';\n      return 0;\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u53bb\u770b\u9898\u89e3\u5927\u4f6c\u6253\u7684\u770b\u4e0d\u61c2&#8230;\u53ea\u597d\u81ea\u5df1\u52aa\u529b\uff08\u8fde\u8499\u5e26\u6284\uff09\u5199\u4e86\u597d\u4e45\u7ec8\u4e8e\u8fc7\u4e86 \u7adf [&#8230;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-138","post","type-post","status-publish","format-standard","hentry","category-2"],"_links":{"self":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts\/138","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=138"}],"version-history":[{"count":0,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts\/138\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=138"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=138"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}