POJ2485题解

 1 #include<stdio.h>
 2 #include<algorithm>
 3 using namespace std;
 4 struct shit{
 5     int in;
 6     int to;
 7     int v;
 8 }e[251000];
 9 int dep[251000],T,back,father[251000],ans,n,a;
10 bool cmp(shit a,shit b)
11 {
12     if(a.v<b.v)return true;
13     else return false;
14 }
15 int get_father(int s)
16 {
17     return father[s]=father[s]==s?s:get_father(father[s]);
18 }
19 void add(int val,int ii,int jj)
20 {
21     e[++back].v=val;
22     e[back].in=ii;
23     e[back].to=jj;
24 }
25 void scan()
26 {
27     scanf("%d",&n);
28     for(int i=1;i<=n;i++)
29             for(int j=1;j<=n;j++)
30                 {
31                     scanf("%d",&a);
32                     if(i!=j)add(a,i,j);
33                 }
34     sort(e+1,e+back+1,cmp);
35 }
36 void work()
37 {
38     int too,inn;
39     for(int i=1;i<=n;i++)
40     father[i]=i;
41     for(int i=1;i<=back;i++)
42     {
43         too=get_father(e[i].to);inn=get_father(e[i].in);
44         if(too!=inn)
45         {
46             if(dep[too]>dep[inn])father[inn]=too;
47             if(dep[too]<dep[inn])father[too]=inn;
48             if(dep[too]==dep[inn]){
49                 father[inn]=too;
50                 dep[too]++;
51             }
52             ans=e[i].v;
53         }
54     }
55 }
56 int main()
57 {
58     scanf("%d",&T);
59     while(T--)
60     {
61         scan();
62         work();
63         printf("%d\n",ans);
64         back=0;
65     }
66     return 0;
67 }