icpc/uf.hpp

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• Last update: 2023-05-31 02:53:46+09:00
• Include: #include "icpc/uf.hpp"
• Link: https://onlinejudge.u-aizu.ac.jp/problems/3324

Depends on

• icpc/template.hpp

Code

#pragma once

#include "icpc/template.hpp"

// https://onlinejudge.u-aizu.ac.jp/problems/3324

struct UF {
    V<int> par;

    UF() {}
    UF(int n) : par(n, -1) {}

    int leader(int x) { return par[x] < 0 ? x : par[x] = leader(par[x]); }

    bool merge(int x, int y) {
        x = leader(x), y = leader(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y);
        par[x] += par[y];
        par[y] = x;
        return true;
    }

    bool same(int x, int y) { return leader(x) == leader(y); }

    int size(int x) { return -par[leader(x)]; }
};

#line 2 "icpc/uf.hpp"

#line 2 "icpc/template.hpp"

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
#define REP(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;
template <class T> ostream& operator<<(ostream& os, const V<T>& v) {
    os << "[ ";
    for (auto& vi : v) os << vi << ", ";
    return os << "]";
}

#ifdef LOCAL
#define show(x) cerr << __LINE__ << " : " << #x << " = " << x << endl;
#else
#define show(x) true
#endif

using uint = unsigned int;
using ull = unsigned long long;

// g++ -g -fsanitize=undefined,address -DLOCAL -std=gnu++17
#line 4 "icpc/uf.hpp"

// https://onlinejudge.u-aizu.ac.jp/problems/3324

struct UF {
    V<int> par;

    UF() {}
    UF(int n) : par(n, -1) {}

    int leader(int x) { return par[x] < 0 ? x : par[x] = leader(par[x]); }

    bool merge(int x, int y) {
        x = leader(x), y = leader(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y);
        par[x] += par[y];
        par[y] = x;
        return true;
    }

    bool same(int x, int y) { return leader(x) == leader(y); }

    int size(int x) { return -par[leader(x)]; }
};

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