P1983-车站分级 

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 #define pb push_back
 4 #define _for(i,a,b) for(int i = (a);i < (b);i ++)
 5 #define INF 100000003
 6 #define ll long long
 7 inline ll read()
 8 {
 9     ll ans = 0;
10     char ch = getchar(), last = ' ';
11     while(!isdigit(ch)) last = ch, ch = getchar();
12     while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
13     if(last == '-') ans = -ans;
14     return ans;
15 }
16 inline void write(ll x)
17 {
18     if(x < 0) x = -x, putchar('-');
19     if(x >= 10) write(x / 10);
20     putchar(x % 10 + '0');
21 }
22 int n,m;
23 int a[1003][1003];
24 int in[1003];
25 int ans = 1;
26 vector<int> G[1003];
27 void toposort()
28 {
29     queue<int> q;
30     _for(j,1,n+1)
31     {
32         int sum = 0;
33         _for(i,1,n+1)
34         if(a[i][j])
35             G[i].pb(j),sum ++;
36         in[j] = sum;
37     }
38 
39     _for(i,1,n+1)
40         if(!in[i])
41             q.push(i);
42     q.push(0);
43     while(q.size()!=1)
44     {
45         int x = q.front();
46         q.pop();
47         if(!x)
48         {
49             q.push(0);
50             ans ++;
51             continue;
52         }
53         _for(i,0,G[x].size())
54         {
55             in[G[x][i]] --;
56             if(!in[G[x][i]])
57                 q.push(G[x][i]);
58         }
59     }
60 }
61 int main()
62 {
63     n = read(), m = read();
64     _for(i,1,m+1)
65     {
66         int t = read();
67         set<int> s;
68         int st,ed;
69         _for(j,1,t+1)
70         {
71             int k = read();
72             if(j==1)
73                 st = k;
74             else if(j==t)
75                 ed = k;
76             s.insert(k);
77         }
78         _for(j,st+1,ed)
79             if(!s.count(j))
80                 for(auto p:s)
81                     a[j][p] = 1;
82     }
83     toposort();
84     write(ans);
85     return 0;
86 }

 

posted @ 2019-09-16 16:59  Asurudo  阅读(154)  评论(0)    收藏  举报