蓝桥杯 国王的烦恼 反向并查集

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<algorithm>
#include<string>
#include<map>
#include<queue>
#include<stack>
#include<set>
#include<vector>
using namespace std;
const int maxn=1e4+10;
const double eps=1e-6;
struct node
{
int a1,a2,t;
}bridge[100010];
int n,m;
int f[maxn];
int cmp(node x,node y)
{
return x.t>y.t;
}
int find(int x)
{
return f[x]==x?x:f[x]=find(f[x]);
}
int main()
{
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++) f[i]=i;
int day=0;
for(int i=0;i<m;i++)
{
scanf("%d%d%d",&bridge[i].a1,&bridge[i].a2,&bridge[i].t);
if(bridge[i].t>day)
day=bridge[i].t;
}
sort(bridge,bridge+m,cmp);
int sum=0;
int i=0;
while(day>0)
{
while(bridge[i].t==day)
{
int u=find(bridge[i].a1),v=find(bridge[i].a2);
if(u!=v)
{
f[u]=v;
sum++;
break;
}
else
i++;
}
while(bridge[i].t==day)
{
int u=find(bridge[i].a1),v=find(bridge[i].a2);
f[u]=v;
i++;
}
day--;
}
cout<<sum<<endl;

return 0;
}