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Civilization

                                           Civilization


#include <iostream>
#include <vector>
#include <stdio.h>
#define sf(i) scanf("%d", &i)
#define pf(i) printf("%d\n", i)
#define pb push_back
using namespace std;

const int N = 3e5 + 1;
vector<int> g[N];
int parent[N];
int diameter[N];
bool isUsed[N];
int n, m, q, maxi, maxiv;

int rad(int a)
{
    return (diameter[a] + 1) / 2;
}
int find(int a)
{
    if(parent[a] == a)
    {
        return a;
    }
    return parent[a] = find(parent[a]);
}

void unite1(int a, int b)
{
    a = find(a);
    b = find(b);
    if(a > b)
        swap(a, b);
    parent[b] = a;
}

void unite(int a, int b)
{
    a = find(a);
    b = find(b);
    if(a > b)
    {
        swap(a, b);
    }

    parent[b] = a;

    diameter[a] = max(rad(a) + rad(b) + 1, max(diameter[a], diameter[b]));

}

void dfs(int v, int depth, int p)
{
    if(depth > maxi)
    {
           maxi = depth;
           maxiv = v;
    }
    for(int i = 0; i < g[v].size(); i++)
    {
        if(g[v][i] == p)
            continue;
        dfs(g[v][i], depth + 1, v);
    }
}
int findLongestWay(int i)
{
    maxi = -1;
    dfs(i, 0, -1);
    maxi = -1;
    dfs(maxiv, 0, -1);
    return maxi;
}
int main()
{
    int a, b, x, y, num;
    sf(n), sf(m), sf(q);

    for(int i = 0; i <= n; i++)
    {
        parent[i] = i;
        diameter[i] = 0;
        isUsed[i] = false;
    }

    for(int i = 0; i < m; i++)
    {
        sf(a), sf(b);
        g[a].pb(b);
        g[b].pb(a);
        if(find(a) != find(b))
            unite1(a, b);
    }

    for(int i = 1; i <= n; i++)
    {
        int p = find(i);
        if(!isUsed[p])
        {
            isUsed[p] = true;
            diameter[p] = findLongestWay(i);
        }
    }

    for(int i = 0; i < q; i++)
    {
        sf(num);
        if(num == 1)
        {
            sf(x);
            x = find(x);
            pf(diameter[x]);
        }
        else
        {
            sf(x), sf(y);
            if(find(x) != find(y))
                unite(x, y);
        }

    }
    return 0;
}

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