{"id":341,"date":"2010-08-11T20:19:00","date_gmt":"2010-08-11T12:19:00","guid":{"rendered":"http:\/\/localhost\/?p=341"},"modified":"2010-08-11T20:19:00","modified_gmt":"2010-08-11T12:19:00","slug":"interconnect_interconnect","status":"publish","type":"post","link":"https:\/\/www.shuizilong.com\/wjmzbmr\/?p=341","title":{"rendered":"Interconnect Interconnect"},"content":{"rendered":"\n

Interconnect Interconnect<\/p>\n

Time Limit:10000MS  Memory Limit:65536K
Total Submit:48 Accepted:37
Case Time Limit:1000MS<\/p>\n

Description <\/strong><\/p>\n

\u7ed9\u51fa\u65e0\u5411\u56feG(V, E). \u6bcf\u6b21\u64cd\u4f5c\u4efb\u610f\u52a0\u4e00\u6761\u975e\u81ea\u73af\u7684\u8fb9(u, v), \u6bcf\u6761\u8fb9\u7684\u9009\u62e9\u662f\u7b49\u6982\u7387\u7684. \u95ee\u4f7f\u5f97G\u8fde\u901a\u7684\u671f\u671b\u64cd\u4f5c\u6b21\u6570. (|V| <= 30, |E| <= 1000) <\/p>\n

Input <\/strong><\/p>\n

\u7b2c\u4e00\u884c\u4e24\u4e2a\u6574\u6570N,M
1<=N<=30
0<=M<=1000
\u63a5\u4e0b\u6765M\u884c,\u6bcf\u884c\u4e24\u4e2a\u6574\u6570X,Y\u8868\u793a\u4e24\u8005\u4e4b\u95f4\u5df2\u4fee\u597d\u4e00\u6761\u9053\u8def.
\u4e24\u70b9\u4e4b\u95f4\u53ef\u4ee5\u4e0d\u6b62\u4fee\u4e86\u4e00\u6761\u8def,\u4e5f\u6709\u53ef\u80fdM\u6761\u8def\u5df2\u4f7fN\u4e2a\u70b9\u6210\u4e3a\u4e00\u4e2a\u6574\u4f53. <\/p>\n

Output <\/strong><\/p>\n

\u8f93\u51fa\u4e00\u4e2a\u5c0f\u6570,\u8868\u793a\u65b0\u4fee\u9053\u8def\u6761\u6570\u7684\u671f\u671b\u503c,\u4fdd\u7559\u516d\u4f4d\u5c0f\u6570.<\/p>\n

Sample Input <\/strong><\/p>\n

4 2
1 2
3 4<\/p>\n

Sample Output <\/strong><\/p>\n

1.500000<\/p>\n

Source
\u8fd9\u4e2a\u9898\u76ee\u6211\u770b\u5230\u4e4b\u540e\u7b2c\u4e00\u611f\u89c9\u5c31\u662f\u72b6\u6001\u538b\u7f29Dp\u3002\u3002
\u72b6\u6001\u5c31\u662f\u5404\u4e2a\u8054\u901a\u5757\u7684\u5927\u5c0f\u3002\u3002
\u7136\u540e\u53d1\u73b0\u72b6\u6001\u6700\u591a\u53ea\u67095604\u4e2a\u3002\u3002
\u7136\u540e\u5c31\u53ef\u4ee5\u65e0\u538b\u529bDp\u4e86\u3002\u3002
\u4e3a\u4e86\u65b9\u4fbf\u6211\u4f7f\u7528\u4e86Map\u5b58\u6570\u636e\uff0cvector\u5b58\u72b6\u6001\uff0c
\u901f\u5ea6\u5947\u6162\u65e0\u6bd4\u3002\u3002
<\/strong><\/p>\n

#include <vector>
#include <algorithm>
#include <utility>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <set>
#include <map>
#include <cstring>
#include <time.h>
#define rep(i,n) for(int i=0;i<n;i++)
#define pb push_back
#define Debug(x) cout<<#x<<"="<<x<<endl;
#define For(i,l,r) for(int i=l;i<=r;i++)
#define tr(e,x) for(VI::iterator e=x.begin();e!=x.end();e++)
#define printTime cout<<"Time:"<<pre-clock()<<endl;pre=clock();
const int inf=~0U>>1;
using namespace std;
typedef vector<int> VI;
map<VI,double> Map;
int n,m;
int total;
double Dp(VI A)
{
if(Map.count(A))return Map[A];
double&x=Map[A];
if(A.size()==1)return x=0;
double same=0;
rep(i,A.size())
rep(j,i+1)
if(i==j)
same+=double(A[i]*(A[i]-1)\/2)\/total;
else
{
VI New=A;
New[i]+=New[j];swap(New[j],New[New.size()-1]);
New.pop_back();sort(New.begin(),New.end());
x+=double(A[i]*A[j])\/total*Dp(New);
}
x=(x+1)\/(1-same);
return x;
}
int main()
{
\/\/freopen("in","r",stdin);
cin>>n>>m;total=n*(n-1)\/2;
VI comp(n);
rep(i,n)comp[i]=i;
int s,t;
rep(i,m)
{
cin>>s>>t;–s;–t;int that=comp[t];
if(comp[s]!=comp[t])
rep(j,n)if(comp[j]==that)
comp[j]=comp[s];
}
VI count(n,0),Now;
rep(i,n)count[comp[i]]++;
rep(i,n)if(count[i])Now.pb(count[i]);
sort(Now.begin(),Now.end());
printf("%0.6lfn",Dp(Now));
\/\/cout<<Map.size()<<endl;
}<\/p>\n","protected":false},"excerpt":{"rendered":"

Interconnect Interconnect Time Limit:10000MS  Memory Limit:65536KTotal Submit:48 Accepted:37 Case Time Limit:1000MS Description \u7ed9\u51fa\u65e0\u5411\u56feG(V, E). \u6bcf\u6b21\u64cd\u4f5c\u4efb\u610f\u52a0\u4e00\u6761\u975e\u81ea\u73af\u7684\u8fb9(u, v), \u6bcf\u6761\u8fb9\u7684\u9009\u62e9\u662f\u7b49\u6982\u7387\u7684. \u95ee\u4f7f\u5f97G\u8fde\u901a\u7684\u671f\u671b\u64cd\u4f5c\u6b21\u6570. (|V| <= 30, |E| <= 1000) Input \u7b2c\u4e00\u884c\u4e24\u4e2a\u6574\u6570N,M 1<=N<=30 0<=M<=1000 \u63a5\u4e0b\u6765M\u884c,\u6bcf\u884c\u4e24\u4e2a\u6574\u6570X,Y\u8868\u793a\u4e24\u8005\u4e4b\u95f4\u5df2\u4fee\u597d\u4e00\u6761\u9053\u8def. \u4e24\u70b9\u4e4b\u95f4\u53ef\u4ee5\u4e0d\u6b62\u4fee\u4e86\u4e00\u6761\u8def,\u4e5f\u6709\u53ef\u80fdM\u6761\u8def\u5df2\u4f7fN\u4e2a\u70b9\u6210\u4e3a\u4e00\u4e2a\u6574\u4f53. Output \u8f93\u51fa\u4e00\u4e2a\u5c0f\u6570,\u8868\u793a\u65b0\u4fee\u9053\u8def\u6761\u6570\u7684\u671f\u671b\u503c,\u4fdd\u7559\u516d\u4f4d\u5c0f\u6570. Sample Input 4 21 2 3 4 Sample Output 1.500000 Source\u8fd9\u4e2a\u9898\u76ee\u6211\u770b\u5230\u4e4b\u540e\u7b2c\u4e00\u611f\u89c9\u5c31\u662f\u72b6\u6001\u538b\u7f29Dp\u3002\u3002\u72b6\u6001\u5c31\u662f\u5404\u4e2a\u8054\u901a\u5757\u7684\u5927\u5c0f\u3002\u3002\u7136\u540e\u53d1\u73b0\u72b6\u6001\u6700\u591a\u53ea\u67095604\u4e2a\u3002\u3002\u7136\u540e\u5c31\u53ef\u4ee5\u65e0\u538b\u529bDp\u4e86\u3002\u3002\u4e3a\u4e86\u65b9\u4fbf\u6211\u4f7f\u7528\u4e86Map\u5b58\u6570\u636e\uff0cvector\u5b58\u72b6\u6001\uff0c\u901f\u5ea6\u5947\u6162\u65e0\u6bd4\u3002\u3002 #include <vector>#include <algorithm>#include <utility>#include <iostream>#include <cstdio>#include <cmath>#include <cstdlib>#include <set>#include <map>#include <cstring>#include <time.h>#define […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[10],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=\/wp\/v2\/posts\/341"}],"collection":[{"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=341"}],"version-history":[{"count":0,"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=\/wp\/v2\/posts\/341\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=341"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=341"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.shuizilong.com\/wjmzbmr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=341"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}