Cod sursa(job #3239337)

Utilizator stefanrotaruRotaru Stefan-Florin stefanrotaru Data 4 august 2024 16:27:44
Problema Arbore partial de cost minim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.59 kb
#include <fstream>
#include <algorithm>
#include <vector>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#pragma once
#pragma optimize("o", on)
#pragma optimize("", off)
#pragma inline_recursion(on)
#pragma inline_depth(255)
#pragma unroll (4)
#pragma ivdep
#pragma loop(no_vector)
#pragma GCC optimize ("O3")
#pragma GCC target ("arch=skylake")
#pragma message("Compiling " __FILE__ "...")

using namespace std;

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
} f("apm.in");

ofstream g("apm.out");

int n, m, cost;

vector <int> sz, parinte;

vector <pair <int, int> > ans;

struct graf
{
    int x, y, cost;
} a[200005];

bool comp(graf &a, graf &b)
{
    return a.cost < b.cost;
}

int find(int x)
{
    if (parinte[x] != x) {
        return parinte[x] = find(parinte[x]);
    }

    return parinte[x];
}

void Union(int x, int y)
{
    int a = find(x), b = find(y);

    if (a != b) {
        if (sz[a] < sz[b]) {
            swap (a, b);
        }

        sz[a] += sz[b];
        parinte[b] = a;
    }
}

int main()
{
    f >> n >> m;

    sz.resize(n + 1), parinte.resize(n + 1);

    for (int i = 1; i <= m; ++i) {
        f >> a[i].x >> a[i].y >> a[i].cost;
    }

    for (int i = 1; i <= n; ++i) {
        parinte[i] = i;
        sz[i] = 1;
    }

    sort(a + 1, a + m + 1, comp);

    for (int i = 1; i <= m; ++i) {
        if (find(a[i].x) != find(a[i].y)) {
            cost += a[i].cost;
            ans.push_back({a[i].x, a[i].y});
            Union(a[i].x, a[i].y);
        }
    }

    g << cost << '\n' << ans.size() << '\n';

    for (auto [a, b] : ans) {
        g << a << ' ' << b << '\n';
    }

    return 0;
}