UVA_10608_Friends

#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#pragma warning(disable:4996)
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
class DisjoinSet
{
private:
vector<int>represent, rank;
public:
DisjoinSet(const int &n):represent(n),rank(n)
{
for (int i = 0; i < n; i++)
{
represent[i] = i;
}
}
int find(int i)
{
return represent[i] = represent[i] == i ? i : find(represent[i]);
}
void merge(const int &x, const int &y)
{
auto a = find(x);auto b = find(y);
if (rank[a] < rank[b])
{
represent[a] = b;
}
else
{
represent[b] = a;
if (rank[b] == rank[a])
{
rank[a]++;
}
}
}
int max()
{
map<int, int>union_amount;
for (size_t i = 0; i < represent.size(); i++)
{
union_amount[find(i)]++;
}
int maximum = 0;
for (auto iter = union_amount.begin(); iter != union_amount.end(); iter++)
{
maximum = std::max(maximum, iter->second);
}
return maximum;
}
};
int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
int T; cin >> T;
while (T--)
{
int n, m; cin >> n >> m;
DisjoinSet union_set(n);
while (m--)
{
int first, second; cin >> first >> second;
if (first > second)
{
std::swap(first, second);
}
union_set.merge(first-1, second-1);
}
cout << union_set.max() << endl;
}
return 0;
}