并查集 HDU 1856
#include<iostream>
#include<stdio.h>
using namespace std;
int father[10000001],num[10000001];
/**//*初始化数组*/
void makeset(int x)
{
for(int i=0;i<=x;i++)
{
father[i]=i;
num[i]=1;
}
}
int findset(int x)//查
{
if(x!=father[x])
{
father[x]=findset(father[x]);
}//回溯
return father[x];
}
void Union(int a,int b)//并
{
int x=findset(a);
int y=findset(b);
if(x==y)
{
return;
}
if(num[x]>=num[y])
{
father[y]=x;
num[x]+=num[y];
}
else
{
father[x]=y;
num[y]+=num[x];
}
}
int main()
{ int n;
while(scanf("%d",&n)!=EOF)
{
makeset(10000000);
for(int i=1;i<=n;i++)
{
int first,second;
scanf("%d%d",&first,&second);
Union(first,second);
}
int max=-99999;
for(int i=1;i<=10000000;i++)
{
if(num[i]>max)
max=num[i];
}
printf("%d\n",max);
}
return 0;
}
#include<stdio.h>
using namespace std;
int father[10000001],num[10000001];
/**//*初始化数组*/
void makeset(int x)
{
for(int i=0;i<=x;i++)
{
father[i]=i;
num[i]=1;
}
}
int findset(int x)//查
{
if(x!=father[x])
{
father[x]=findset(father[x]);
}//回溯
return father[x];
}
void Union(int a,int b)//并
{
int x=findset(a);
int y=findset(b);
if(x==y)
{
return;
}
if(num[x]>=num[y])
{
father[y]=x;
num[x]+=num[y];
}
else
{
father[x]=y;
num[y]+=num[x];
}
}
int main()
{ int n;
while(scanf("%d",&n)!=EOF)
{
makeset(10000000);
for(int i=1;i<=n;i++)
{
int first,second;
scanf("%d%d",&first,&second);
Union(first,second);
}
int max=-99999;
for(int i=1;i<=10000000;i++)
{
if(num[i]>max)
max=num[i];
}
printf("%d\n",max);
}
return 0;
}