2017.7.10 noi2008 假面舞会

  1 #include<cstdio>
  2 #include<cstring>
  3 #include<iostream>
  4 #include<algorithm>
  5 #include<vector>
  6 #define mem(a,b) memset(a,b,sizeof(a))
  7 using namespace std;
  8 int read()
  9 {
 10     int ans=0;char q=getchar();
 11     while(q<‘0‘||q>‘9‘)q=getchar();
 12     while(q>=‘0‘&&q<=‘9‘){ans=ans*10+q-‘0‘;q=getchar();}
 13     return ans;
 14 }
 15 int gcd(int x,int y){return y==0?x:gcd(y,x%y);}
 16 int abss(int x){return x<0?-x:x;}
 17 int maxn(int a,int b){return a>b?a:b;}
 18 int minn(int a,int b){return a<b?a:b;}
 19 struct son
 20 {
 21     int v,next,w;
 22 };
 23 son a1[6000001];
 24 int first[6000001],e;
 25 
 26 void addbian(int u,int v,int w)
 27 {
 28     a1[e].w=w;
 29     a1[e].v=v;
 30     a1[e].next=first[u];
 31     first[u]=e++;
 32 }
 33 
 34 int n,m,u,o;
 35 int vis[600001];
 36 int ans;
 37 int w[600001];
 38 int maxl,minl;
 39 
 40 void dfs(int fa,int x,int val)
 41 {
 42     //printf("x=%d val=%d\n",x,val);
 43     vis[x]=1;
 44     w[x]=val;
 45     for(int i=first[x];i!=-1;i=a1[i].next)
 46     {
 47         int temp=a1[i].v;
 48         if(temp==fa)continue;
 49         if(vis[temp])
 50         {
 51             if(val==0)continue;
 52             ans=gcd(ans,abss(val+a1[i].w-w[temp]));
 53             //printf("val=%d temp=%d ans=%d\n",val,temp,ans);
 54             continue;
 55         }
 56         dfs(x,temp,val+a1[i].w);
 57     }
 58 }
 59 
 60 void dfs2(int fa,int x,int val)
 61 {
 62     vis[x]=1;
 63     maxl=maxn(maxl,val);
 64     minl=minn(minl,val);
 65     for(int i=first[x];i!=-1;i=a1[i].next)
 66     {
 67         int temp=a1[i].v;
 68         if(vis[temp]||temp==fa)continue;
 69         dfs2(x,temp,val+a1[i].w);
 70     }
 71 }
 72 
 73 int main(){
 74     //freopen("party.in","r",stdin);
 75     //freopen("party.out","w",stdout);
 76     /////freopen("1.txt","r",stdin);
 77     //freopen("2.txt","w",stdout);
 78     mem(first,-1);
 79     n=read();m=read();
 80     for(int i=1;i<=m;++i)
 81     {
 82         u=read();o=read();
 83         addbian(u,o,1);
 84         addbian(o,u,-1);
 85     }
 86     //cout<<0;
 87     for(int i=1;i<=n;++i)
 88     {
 89         if(vis[i])continue;
 90         dfs(-1,i,0);
 91     }
 92     
 93     if(ans)
 94     {
 95         if(ans<3)
 96           printf("-1 -1");
 97         else
 98         {
 99             printf("%d ",ans);
100             for(int i=3;i<=ans;++i)
101               if(!(ans%i))
102               {
103                 printf("%d",i);
104                     break;
105                 }
106         }
107     }
108     else
109     {
110         mem(w,0);
111         mem(vis,0);
112         for(int i=1;i<=n;++i)
113         {
114             if(vis[i])continue;
115             maxl=minl=0;
116             dfs2(-1,i,0);
117             //ans=maxn(maxl1+maxl2-1,ans);
118             ans+=(maxl-minl+1);
119         }
120         //printf("ans=%d\n",ans);
121         if(ans<3)
122           printf("-1 -1");
123         else
124           printf("%d 3",ans);
125     }
126         
127     //while(1);
128     return 0;
129 }