URAL1291. Gear-wheels

１２９１

不知道为嘛被分在ＤＰ里了　瞎写　注意没被别的轮带动的情况　初始为０　　分母为１

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<queue>
 using namespace std;
 #define N 1010
 vector<int>ge[N];
 int co[N],d[N],vis[N];
 struct node
 {
     int f,nu,de;
 }p[N];
 int gcd(int a,int b)
 {
     return b==?a:gcd(b,a%b);
 }
 void init(int x,int y)
 {
     int n1 = co[x]*p[x].nu,n2 = co[y]*p[x].de;
     if(n1==||n2==) n2=;
     else
     {
         int k = gcd(n1,n2);
         n1 = n1/k;n2 = n2/k;
     }
     if(d[y]==)
     p[y].f = ;
     else
     p[y].f = -;
     p[y].nu = n1;
     p[y].de = n2;
 }
 void bfs(int u)
 {
     queue<int>q;
     q.push(u);
     while(!q.empty())
     {
         int tu = q.front();
         q.pop();
         for(int i =  ; i < (int)ge[tu].size() ; i++)
         {
             int v = ge[tu][i];
             if(!vis[v])
             {
                 vis[v] = ;
                 d[v] = -d[tu];
                 init(tu,v);
                 q.push(v);
             }
         }
     }
 }
 int main()
 {
     int i,n,s,v;
     scanf("%d",&n);
     for(i = ; i <= n ; i++)
     {
         scanf("%d",&co[i]);
         int a;
         while(scanf("%d",&a)&&a)
         ge[i].push_back(a);
     }
     scanf("%d%d",&s,&v);
     d[s] = ;
     p[s].f = ;
     p[s].nu = v;
     p[s].de = ;
     vis[s] = ;
     bfs(s);
     for(i = ; i <= n ; i++)
     {
         if(p[i].f==-&&p[i].nu)
         printf("-");
         if(p[i].nu==)
         p[i].de = ;
         printf("%d/%d\n",p[i].nu,p[i].de);
     }
     return ;
 }