HDU 1325 Judging if the graph is a tree

Test instructions: Judging if the graph is a tree

Link: Point Me

This problem with and check the set to determine connectivity, connectivity and only 1 into the degree of 0, the remaining penetration is 1, is the tree

1#include <cstdio>2#include <iostream>3#include <algorithm>4#include <cstring>5#include <cmath>6#include <queue>7#include <map>8 using namespacestd;9 #defineMOD 1000000007Ten Const intinf=0x3f3f3f3f; One Const Doubleeps=1e-5; A #defineCL (a) memset (A,0,sizeof (a)) - #defineTS printf ("*****\n"); - Const intmaxn=1000000; the intN,m,tt; - intA[MAXN]; - intF[MAXN]; - int inch[MAXN]; + BOOLVIS[MAXN]; - intFindintx) + { A     if(f[x]==-1)returnx; at     Else returnf[x]=find (F[x]); - } - voidBingintXinty) - { -     intt1=find (x); -     intT2=find (y); in     if(t1!=T2) -f[t1]=T2; to } + intMain () - { the     inti,j,k; * #ifndef Online_judge $Freopen ("1.in","R", stdin);Panax Notoginseng     #endif -     intCnt=0; the     intu,v; +     intIcase=0; A     BOOLflag=true; thememset (f,-1,sizeof(f)); +memset (Vis,false,sizeof(Vis)); -Memsetinch,0,sizeof(inch)); $      while(SCANF ("%d%d", &u,&v)! =EOF) $     { -         if(u==-1&&v==-1) Break; -         if(u==0&&v==0) the         { -icase++;Wuyiprintf"Case %d", icase); the             intt0=0; -              for(i=0; i<cnt;i++) Wu             { -                 if(Find (A[i])!=find (a[0])) About                 { $flag=0; -                      Break; -                 } -                 if(inch[a[i]]==0) t0++; A                 Else if(inch[a[i]]>1) +                 { theflag=0; -                      Break; $                 } the             } the             if(t0!=1) flag=false; the             if(cnt==0) flag=true; the             if(flag) printf ("Is a tree.\n"); -             Elseprintf"is not a tree.\n"); inCnt=0; thememset (f,-1,sizeof(f)); thememset (Vis,false,sizeof(Vis)); AboutMemsetinch,0,sizeof(inch)); theflag=true; the         } the         Else +         { -             if(!Vis[u]) the             {Bayivis[u]=1; thea[cnt++]=u; the             } -             if(!Vis[v]) -             { thevis[v]=1; thea[cnt++]=v; the             } the             if(Find (U) ==find (v)) flag=0; -             Else the             { the Bing (u,v); the                 inch[v]++;94             } the         } the     } the}

HDU 1325 Judging if the graph is a tree