题目：http://www.lydsy.com/JudgeOnline/problem.php?id=1006
题解：这题应该是留的最久的一个坑了吧。。。今天终于A掉了。。。但还是没有完全理解的感觉。
代码：
1 #include<cstdio>
2 #include<cstdlib>
3 #include<cmath>
4 #include<cstring>
5 #include<algorithm>
6 #include<iostream>
7 #include<vector>
8 #include<map>
9 #include<set>
10 #include<queue>
11 #include<string>
12 #include<bitset>
13 #define inf 1000000000
14 #define maxn 2000000+5
15 #define maxm 10000000
16 #define eps 1e-10
17 #define ll long long
18 #define pa pair<int,int>
19 #define for0(i,n) for(int i=0;i<=(n);i++)
20 #define for1(i,n) for(int i=1;i<=(n);i++)
21 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
22 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
23 #define for4(i,x) for(int i=head[x],y=e[i].go;i;i=e[i].next,y=e[i].go)
24 #define mod 1000000007
25 #define lch k<<1,l,mid
26 #define rch k<<1|1,mid+1,r
27 using namespace std;
28 inline int read()
29 {
30 int x=0,f=1;char ch=getchar();
31 while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
32 while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
33 return x*f;
34 }
35 int n,m,tot,head[maxn],id[maxn],pos[maxn],v[maxn];
36 priority_queue<pa>q;
37 struct edge{int go,next;}e[maxn];
38 inline void add(int x,int y)
39 {
40 e[++tot]=(edge){y,head[x]};head[x]=tot;
41 e[++tot]=(edge){x,head[y]};head[y]=tot;
42 }
43 int main()
44 {
45 freopen("input.txt","r",stdin);
46 freopen("output.txt","w",stdout);
47 n=read();m=read();
48 for1(i,m)add(read(),read());
49 for1(i,n)q.push(pa(0,i));
50 for3(i,n,1)
51 {
52 while(id[q.top().second])q.pop();
53 int x=q.top().second;q.pop();
54 for4(j,x)if(!id[y])q.push(pa(++v[y],y));
55 id[x]=i;pos[i]=x;
56 }
57 int ans=1;
58 for1(i,n)
59 {
60 int tmp=0;
61 for4(j,i)if(id[y]>id[i])tmp++;
62 ans=max(ans,tmp+1);
63 }
64 cout<<ans<<endl;
65 return 0;
66 }
时间： 2024-10-12 19:36:08