tyvj P1403 关押罪犯 题解

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<cmath>
 5 #include<algorithm>
 6 #include<queue>
 7 #include<cstdlib>
 8 #include<iomanip>
 9 #include<cassert>
10 #include<climits>
11 #define maxn 100001
12 #define F(i,j,k) for(int i=j;i<=k;i++)
13 #define M(a,b) memset(a,b,sizeof(a))
14 #define FF(i,j,k) for(int i=j;i>=k;i--)
15 #define inf 0x7fffffff
16 #define p 23333333333333333
17 using namespace std;
18 int read(){
19     int x=0,f=1;char ch=getchar();
20     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
21     while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
22     return x*f;
23 }
24 int f[maxn];
25 struct sd
26 {
27     int a;
28     int b;
29     int c;
30     int next;
31 }edge[maxn];
32 bool cmp(const sd& x,const sd& y)
33 {
34     return x.c>y.c;
35 }
36 int find(int x) 
37 {
38     return f[x]==x?x:f[x]=find(f[x]);
39 }
40 int head[maxn];
41 int cnt=1;
42 int addedge(int x,int y,int v)
43 {
44     cnt++;
45     edge[cnt].a=x;
46     edge[cnt].b=y;
47     edge[cnt].c=v;
48     edge[cnt].next=head[x];
49     head[x]=cnt;
50 }
51 int main()
52 {
53     std::ios::sync_with_stdio(false);//cout<<setiosflags(ios::fixed)<<setprecision(1)<<y;
54 //  freopen("data.in","r",stdin);
55 //  freopen("data.out","w",stdout);
56     int n,m;
57     cin>>n>>m;
58     F(i,1,m){
59         int x,y,z;
60         cin>>x>>y>>z;
61         addedge(x,y,z);
62     }
63     int x,y;
64     for(int i=1;i<=n*2;i++)
65         f[i]=i;
66     sort(edge+1,edge+m+1,cmp);
67     F(i,1,m){
68         x=find(edge[i].a);
69         y=find(edge[i].b);
70         if(x==y) 
71         {
72             cout<<edge[i].c;
73             return 0;
74         }
75         f[y]=find(edge[i].a+n);
76         f[x]=find(edge[i].b+n);
77     }
78     cout<<"0"<<endl;
79     return 0;
80 }